What countries are not even signatories of the World Heritage Convention?
I went through the list of sovereign or semi-sovereign states. Here is what I came by:
Antigua and Barbuda, the Bahamas, Bhutan, Brunei, Djibouti, East Timor, Equatorial Guinea, Kuwait (a signatory with neither T list nor inscribed properties), Liberia, Liechtenstein, Monaco, Nauru, Rwanda, St Vincent and the Grenadines, Sao Tome and Principe, Sierra Leone, Singapore, Swaziland, Trinidad and Tobago, Tuvalo (all UN members)
as well as non-UN members Abkhazia, Nagorno-Karabakh, Northern Cyprus, Palestinian Territories, Somaliland, South Ossetia, Taiwan, Transnistria and Western Sahara.
For at least some of them it is evident they could inscribe some properties on the list. I know both Taiwan and the Palestinian Territories are in constant contact with Unesco in an attempt to have their nominations recognized despite their disputed international status, so far with little success. What about the rest?

According to the official website

http://whc.unesco.org/en/statesparties/

Antigua and Barbuda, Bhutan, Djibouti, Kuwait, Liberia, Monaco, Rwanda, St Vincent & Grenadines, Sao Tome & Principe, Sierra Leone and Swaziland are actually signatoiries of the WH Convention. Swaziland even has a site on its Tentative List since December 08.

So this leaves us then with:
Bahamas, Brunei, East Timor, Equatorial Guinea, Liechtenstein, Nauru, Singapore, Trinidad and Tobago, Tuvalo and all the disputed states.
Still something to account for but thanks for the correction Khuft.

Does Khuft (or anyone else) understand the logic of which "countries" (State Parties) can participate in the World Heritage Convention (WHC) and therefore the WH scheme? One might have thought that
a. To do so a state would have to be a member of UNESCO
b. To be a member of UNESCO a state would have had to be a member of the UN.
But apparently neither is true!

a. There are 192 members of the UN. We know that acceptance for membership is a diplomatic and political decision taken by members of the Security Council and that some states which might be recognised as fully sovereign by other UN members might not be accepted since they are not acceptable to some Security Council member e.g Taiwan, Kosovo. The UN also maintains 2 other forms of status for "countries"/"states"/"entities" (as well as others for organisations - but they are not relevant here)
i. "Non-member State having received a standing invitation to participate as observer in the sessions and the work of the General Assembly and maintaining permanent observer mission at Headquarters" - The Holy See is the only state in this category
ii. "Entity having received a standing invitation to participate as observer in the sessions and the work of the General Assembly and maintaining permanent observer mission at Headquarters" - Palestine is the only "entity" in this category

b. There are 193 members of UNESCO plus 6 "Associate members"
i. The 193 consists of all 192 UN members except Liechtenstein plus non UN members Cook Islands and Niue.
ii. The 6 "Associate members" are Aruba, British Virgin Islands, Cayman Islands, Macao (!!) Netherlands Antilles and Tokelau. Quite why these "not totally independent states" should be "associate members" whilst Cook Islands/Niue are full members I know not. I know that Tokelau has twice had a referendum and rejected full independence. I suspect this goes back to the UN list of "Non Self-governing territories" which goes back to the "anti colonialist" era! Cook Islands was removed from this list as the UN now considers it "Internally self governing". So Bermuda for instance, that well known "sink of colonial repression" which considers itself certainly as "internally self governing" as Cook Islands can't join UNESCO and can only get its (single) WHS inscribed by UK!! The NL Antilles also managed to escape from this anti colonialism list by some constitutional sleight of hand but, I believe, that its potential sites would still have to be nominated by NL - presumably because it has, unlike Cook Islands, only gone for "Associate memebership" of UNESCO. Another "state" on the anti colonial list is Puerto Rico, despite being a "self governing commonwealth" it can only get sites inscribed by USA.
iii. Singapore only joined as recently as Oct 2007

c. There are 186 State Parties at some stage of ratifying the WHC - i.e "Ratification",
"Acceptance", "Notification of Acceptance" or "Notification of succession" to a previous State Party
i. Of these The Holy See rather strangely is not a Member or Associate Member of UNESCO! It is not quite clear to me therefore on what basis it was allowed to sign the WHC and gain inscriptions!
ii. In addition there are 8 members of UNESCO which are not at an any ratification stage - Bahamas, Brunei, Eq Guinea, Nauru (not of course a UN member), Singapore, Somalia, Timor Leste and Tuvalu. (Assif - Trinidad signed in 2005).
iii. In addition the WHC has not been signed by Liechtenstein (which is not a member of UNESCO either)

I checked what was written in the WH Convention. It states the following:

Article 31

1. This Convention shall be subject to ratification or acceptance by States members of the United Nations Educational, Scientific and Cultural Organization in accordance with their respective constitutional procedures.
2. The instruments of ratification or acceptance shall be deposited with the Director-General of the United Nations Educational, Scientific and Cultural Organization.

Article 32

1. This Convention shall be open to accession by all States not members of the United Nations Educational, Scientific and Cultural Organization which are invited by the General Conference of the Organization to accede to it.
2. Accession shall be effected by the deposit of an instrument of accession with the Director-General of the United Nations Educational, Scientific and Cultural Organization.


I'm not an international lawyer, but from my understanding:
- The Convention only applies to those UNESCO member states that ratify it according to their laws.
- The Convention is open to all other states that wish to join if the General Conference of UNESCO invites them to it.

So this would explain why the Holy See got in, and why other UNESCO members actually are not (yet).

Thanks Khuft - yes that would seem to explain the Holy See "anomaly".
I had a look at the rules for membership of UNESCO too. Here are the sections relevant to the discrepanices vis a vis UN membership :-
"Membership of the UN carries with it the right to membership of UNESCO. States that are not members of UN may be admitted to UNESCO, upon recommendation of the Executive Board, by a two-thirds majority vote of the General Conference.
Territories or groups of territories that are not responsible for the conduct of their international relations may be admitted as Associate Members. Their admission and their rights and obligations are determined by the General Conference"

The Cook Islands would seem to get in to UNESCO with full rather than associate memebership on the basis that they are a "self governing parliamentary democracy in free association with NZ" with some responsibility for their external affairs. Wiki states that "Defence is the responsibility of New Zealand, in consultation with the Cook Islands and at its request. In recent times, the Cook Islands have adopted an increasingly independent foreign policy."

Niue's connection with NZ is similar except that its foreign relations capability seems less clear viz Wiki - "Niue is fully responsible for its internal affairs. Niue's position concerning its external relations is less clear cut. Section 6 of the Niue Constitution Act provides that: "Nothing in this Act or in the Constitution shall affect the responsibilities of Her Majesty the Queen in right of New Zealand for the external affairs and defence of Niue."" UNESCO would appear to have ignored this uncertainly in allowing Niue to join with full membership - but I guess that NZ can't have been worried much!

The net result seems to be that
a. UNESCO can allow any non UN member "state" to join if enough members want it
b. The WHC can be "acceded to" by any "state" even if not a member of UNESCO (or the UN) if UNESCO wants it

But I don't think we will see Transnistria, Abkhazia, S Ossetia, Somaliland or N Cyprus signing up to the WHC any time soon!

En passant, whilst doing my "research" on this subject I noted, with some surprise and even a little amusement, that apparently Liechtenstein recognises neither the Czech Republic or Slovakia (and v.v) because of the Benes Decrees of 1945 concerning the treatment of Czechoslovak citizens of German (and Hungarian) ethnicity and confiscation of property (this coincidentally relates to a recent "Connection" we added concerning the Liechtenstein Family which had property within WHC boundaries within Czechoslovakia confiscated). I can't believe that this has anything to do with Liechtenstein's non-membership of UNESCO and non-accession to the WHC - who knows? But these 2 aspects do prevent yet another European medieval castle (Vaduz) gaining inscription!

I thought it might be interesting to look for potential WHS in countries that currently have no T lists, either because they are not members of Unesco (as with Taiwan, Northern Cyprus, Abkhazia or Western Sahara), because they are no signatories of the WHS conventions (as with Somalia, Timor Leste or South Sudan) or simply because they failed to introduce a T-list (as with Brunei, Rwanda or Liberia). Here are a few relevant websites:

Taiwan (by winterkjm): http://twh.hach.gov.tw/TaiwanE.action
Somalia and Somaliland: http://www.somaliheritage.org/
Northern Cyprus: http://www.cyprusholidayadvisor.com/images/cyprus-map.jpg
Brunei: http://bruneiembassy.be/brunei-eyes-world-heritage-status-for-kg-ayer/
Rwanda: http://newsofrwanda.com/irembo/7654/genocide-memorials-included-unesco-world-heritage /
South Sudan: http://www.lonelyplanet.com/south-sudan
Liberia: http://www.liberianonline.com/modules.php?name=Content&pa=showpage&pid=497
Timor Leste: http://www.cultura.gov.tl/en/institution/projects/recovering-timor-leste-s-traditiona l-architectonic-heritage
Western Sahara: http://www.nickbrooks.org/publications/JNAS_WS_05.pdf
Abkhazia: http://abkhazworld.com/news/misc/834-the-abkhazian-authorities-attach-great-importanc e.html

A few more

Sierra Leone -179th country to adopt the WHC on Jan 7 2005. Was granted c US$30,000 to help develop one on Jan 11 2011. No T List as yet
Cultural Heritage - http://www.sierraleoneheritage.org/sites/monuments/
Natural Heritage - http://apes.eva.mpg.de/apeswiki/index.php/Outamba-Kilimi_National_Park

Djibouti . Ratified the Convention on Nov 30 2007. Was granted c US$30000 to develop a T list on Jan 4 2012 . No T List as yet.
Natural Heritage – Lake Assal ("Measures particularly concerned with the management of salt exploitation activities are to create a protected area of 10 kms, starting from the entrance to the lake, and to classify Lake Assal as a world heritage site. – see section 4.1.8 of https://www2.opic.gov/environasp/eia/lakeassal/Lake_Assal_Salt_Project_EIA_Report_Nov 08.pdf ). Apparently also to include the Ardoukoba Volcano
Cultural Heritage – Seems to be majoring on "Intangible" aspects

St Vincent and Grenadines. Ratified the Convention Feb 3 2003. Oct 11 2010 granted 21352 USD to help develop a T List. No T List as yet.
Cultural Heritage – Yambou Petroglyphs . Possibly as part of a Trans-national nomination of the Caribbean's Rock Art sites. See also "International Seminar on Archaeological Sites of the Caribbean likely to be considered for inscription on the World Heritage List. UNESCO/World Heritage Centre. 19-23 September 2004 Fort-de-France, Martinique"
whc.unesco.org/uploads/events/66-report.doc

Niue. Acceded to the Convention Jan 23 2001. No T List and no request as yet to help produce one but "expects" to have both Natural and Cultural sites . See http://whc.unesco.org/archive/periodicreporting/APA/cycle01/section1/nu-summary.pdf
Possible mixed sites - Huvalu Conservation Area and the Hakupu Heritage Park. See http://www.sprep.org/att/IRC/eCOPIES/Countries/Niue/4.pdf

Kuwait. Ratified the Convention 6 Jun 2002. No T List.
Cultural Heritage – Failaka Island "We are also working on the plan to have some sites on Failaka to be included in the list of UNESCO heritage". See http://www.arabtimesonline.com/NewsDetails/tabid/96/smid/414/ArticleID/181528/reftab/ 69/t/Exclude-sites-from-modernisation-program/Default.aspx and http://www.kuwaitarchaeology.org/al-khidr.html

Singapore. Has not Ratified or Acceded to the Convention – but did rejoin UNESCO in 2007. In 2010 tendered for a ""comprehensive study to assess the feasibility of selected heritage sites ... as possible World Heritage Sites and to recommend a suitable tentative list". Result not known
Most likely site is the Botanic Gardens . See http://www.channelnewsasia.com/stories/singaporelocalnews/view/1050215/1/.html
and http://sg.linkedin.com/pub/nigel-taylor/50/26b/880

Equatorial Guinea. Ratified the Convention 10 Mar 2010. I can find nothing which indicates that a T List is under development nor any likely Cultural Site. It does have 3 National Parks and 3 Ramsar sites. Monte Alen would seem possibly to be the most significant of these. This book on Gorillas suggests it could be a WHS http://books.google.co.uk/books?id=VMtbmkOYD-kC&pg=PA347&lpg=PA347&dq="monte+alen"+UN ESCO+World+Heritage&source=bl&ots=prFZ9H_B-n&sig=nldQJTimJaFJhst6A-f1y0VAaSM&hl=en&sa =X&ei

Sao Tome. Ratified the Convention Jul 25 2006. No public announcement on any T List but some indications in some journals that it is progressing e.g "At present, São Tomé and Príncipe has not yet established a tentative list of universally significant properties within their borders; they are still in the process of doing so. In a workshop conducted in January last year, they began by establishing a pre-inventory of a number of sites, also drafting a tentative listing of Roça Agostinho Neto." From http://www.dac.gov.za/publications/heritage%20booklet/africa%20unknown.pdf
This is the Workshop referred to http://www.epa-prema.net/documents/rapports/report2009.pdf
Roca Agostino Neto is my profile suggestion for a new WHS - made in the earlier days of this Web site - but, having revisited it just 2 years ago and seen its continued decline, it will need more work than I fear little Sao Tome can carry out - even with WMF etc help

Bahamas . Not a signatory to the Convention (only state of the Americas not to)
Bahamian News flash after the 36th UNESCO conference in Paris Oct 2011 - "During the conference, the (Education) Minister also met with the Director General of UNESCO where he discussed The Bahamas' participation in the World Heritage Movement. The Minister told the Director General that The Bahamas has many historical sites that could be included in the registry of World Heritage sites and that he would be looking to advance this cause further on his return home."
BUT an earlier news flash expected Bahamas to sign the Convention by October.
Preachers Cave was to be declared a National Historic/Heritage Park and might be the first nominated site.? http://www.eleutheranews.com/local/1657.html

Tuvalu
Member of UNESCO but hasn't signed the Convention.
Cultural values would seem to be concentrated in the "Intangible" area
Funafati Conservation Area would seem to be the only possible Natural site http://www.timelesstuvalu.com/tuvalu/export/sites/TTO/Attractions/funafuti_conservati on_area.html

So to form a general list of all missing countries:

Not in Unesco:

Liechtenstein, Kosovo, Northern Cyprus, Taiwan, Western Sahara, Transnistria, Abkhazia, South Ossetia, Somaliland.

Unesco members which didn't sign the WH convention:
Bahamas, South Sudan, Somalia, Singapore, Timor Leste, Tuvalu, Nauru.

Member states with no T-list:
Sao Tome, Equatorial Guinea, Kuwait, Niue, Cook Islands, St Vincent, Djibouti, Sierra Leone, Liberia, Rwanda, Brunei, Monaco.

Member states with T-list but no sites inscribed:
Angola, Namibia, Guinea Bissau, Eritrea, Lesotho, Swaziland, Burundi, Chad, Congo (Rep), Comoros, Maldives, Myanmar, Micronesia, Palau, Fiji, Tonga, Samoa, Bhutan, Qatar, Palestine, Jamaica, Trinidad Tobago, Antigua Barbuda, Grenada, Guyana.

Member states with only trans-national sites inscribed:
Zambia, Moldova, Guinea.

Judging by this list (which is biased towards places with a greater number of independent countries) most gaps in the list in the form of unrepresented countries are in Africa, the Caribbean and the Pacific.

Chad and Palau are pretty much ensured to have their first site insribed this year and both look like worthy nominations.

As of late there seems to be at least 1 "first" inscription for a country at most WHC.

Perhaps we should make a connection for first sites inscribed?

Jam - Afghanistan 2002
Butrint - Albania 1992
Beni Hammad - Algeria 1980
Madriu - Andorra 2004
Glaciares - Argentina 1981
Haghpat - Armenia 1996
Baku - Azerbaijan 2000
Dilmun - Bahrain 2005
Bridgetown - Barbados 2011
Bialowieza - Belarus 1992 (with Poland)
Belize Reef - Belize 1996
Abomey - Benin 1985
Potosi - Bolivia 1987
Mostar - Bosnia 2005
Tsodilo - Botswana 2001
Ouro Preto - Brazil 1980
Loropeni - Burkina Faso 2009
Angkor - Cambodia 1992
Dja - Cameroon 1987
Cidade Velha - Cabo Verde 2009
Manovo - CAR 1988
Rapa Nui - Chile 1995
Cartagena - Colombia 1984
Virunga - DR Congo 1979
Talamanca - Costa Rica 1983 (with Panama)
Nimba - Cote d'Ivoire and Guinea 1984
Havana - Cuba 1982
Paphos - Cyprus 1980
Jelling - Denmark 1994
Morne Trios Pitons - Dominica 1997
Santo Domingo - Dom. Rep. 1990
Joya de Ceren - El Salvador 1993
Tallinn - Estonia 1997
Ohrid - Macedonia 1979 (then Yugoslavia)
Lope Okanda - Gabon 2007
Kunta Kinteh - Gambia 2003
Aachen - Germany 1978
Geater Accra - Ghana 1979
Bassae - Greece 1986
Parque National - Haiti 1982
Rome - Holy See 1980 (together with Italy)
Copan - Honduras 1980
Dingvellir - Iceland 2004
Hatra - Iraq 1985
Bend and Boyne - Ireland 1993
Acre - Israel 2001 (occupying the Old City of Jerusalem inscribed 1981)
Valcamonica - Italy 1979
Yasawi - Kazakhstan 2003
Phoenix - Kiribati 2010
Koguryo - North Korea 2004
Suliman To - Kyrgyzstan 2009
Luang Prabang - Laos 1995
Riga - Latvia 1997
Vilnius - Lithuania 1994
Luxemburg - Luxemburg 1994
Tsingy - Madagascar 1990
Lake Malawi - Malawi 1984
Bikini - Marshall Islands 2010
Banc d'Arguin - Mauritania 1989
Aapravasi Ghat - Mauritius 2006
Struve - Moldova 2005 (with many other countries)
Uvs Nuur - Mongolia 2003 (with Russia)
Kotor - Montenegro 1979 (then Yugoslavia)
Fez - Morocco 1981
Mozambique - Mozambique 1991
Schockland - Netherlands 1995
Te Wahipounamu - NZ 1986
Leon Viejo - Nicaragua 2000
Air - Niger 1991
Sukur - Nigeria 1999
Bahla - Oman 1987
Panama - Panama 1980
Kuk - PNG 2008
Jesuits - Paraguay 1993
Danube Delta - Romania 1991
Brimstone - St. Kitts and Nevis 1999
Pitons - St. Lucia 2004
San Marino - San Marino 2008
Al Hijr - Saudi Arabia 2008
Goree - Senegal 1978
Stari Ras - Serbia 1979 (then Yugoslavia)
Aldabra - Seychelles 1982
Skocjan - Slovenia 1988 (then Yugoslavia)
East Rennel - Solomon Islands 1998
Gebel Barkal - Sudan 2003
Central Suriname - Suriname 2000
Drottingholm - Sweden 1991
Damascus - Syria 1979
Sarazm - Tajikistan 2010
Ngorongoro - Tanzania 1979 (as a natural site)
Toukammakou - Togo 2004
Merv - Turkmenistan 1999
Al Ain - UAE 2011
Kiev - Urkaine 1990
Colonia - Uruguay 1995
Itchan Kala - Uzbekistan 1990
Roi Mata's Domain - Vanuatu 2008
Coro - Venezuela 1993
Hue - Vietnam 1993
Shibam - Yemen 1982
Mosi oa Tunya - Zambia 1989 (with Zimbabwe)
Mana - Zimbabwe 1984

Interestingly 32 new countries have been inscribed since 2000.

In theory, for most of these (the exception being Liechtenstein) there are other states claiming their territory which could thus conceivably nominate sites located on their territory.

Kosovo, in any case, already has a site (Medieval monuments of Kosovo), which however is listed under Serbia. Morocco has Parc national de Dakhla on its TL, which is located in Western Sahara, I believe.

BTW -you forgot Nagorno Karabagh; Azerbaijan has Shusha on its TL even though it doesn't control it.

As mentioned above by Khuft a number of "Unrecognised" or "Partially Recognised" countries are controlled de jure by countries which are both UNESCO members and have sites on the inscribed or T Lists (others like Somaliland are not within such a country) . I have tried to check for any potential impact on ones not covered above -

Abkhazia. Recognised by 5 UN countries - Russia, Venezuela, Nicaragua, Tuvalu, Vanuatu and Nauru. I don't think any of Georgia's Inscribed or T List sites are impacted however

S Ossetia This is recognised by 1 fewer UN country than Abkhazia – for some reason Vanuatu hasn't yet got round to joining in doing so! Or perhaps Vanuatan-Ossetian relations are genuinely "strained" at the moment – there must be loads of bilateral issues to exercise their diplomats. Again I haven't been able to identify any Georgian Inscribed or T List sites within its de facto boundaries

Azawad. If ever fully successful in achieving independence would take away from Mali the inscribed sites of Timbuctu and The Tomb of Askia in Gao as well as Es-souk (a Trans-Saharan trading site) from its T List. In any case Mali is not currently "in control" of them.

Bougainville. In order to stop the civil war was promised in 2001 a referendum on Independence from PNG to be held between 2015 and 2020. One presumes this would go the same way as that of S Sudan - though whether PNG would be prepared to let it go is another matter. Again as far as I can see no PNG T List sites are within its boundaries