Actually there are a number of WHS "serviced" by Webcams now – of varying quality, reliability and "up to dateness" (some only up date periodically). But if one wants to see the boats crossing Sydney harbour in front of the Opera House "now" or see absolutely nothing happening at the scientific base on Macquarie Island one can do so!! It depends on time of day of course – Kizhi at night wasn't very illuminating!
However I did find waiting for "Old Faithful" to erupt in the Yellowstone snows worth doing (once!) – even having done it live (once!). Oh, and the Pandas at Wulong were "doing very little" – so little, that they provided a time lapse sequence from the Webcam over several hours, so show some movement
If anyone has a desire to relive a previous visit, to prepare for an upcoming one or even to substitute this rather limited experience for a live visit then here are a few links. As indicated above, the sites are of varying quality- at least one (Blue Mountains) lets one take control of the Webcam's direction and zoom for a couple of minutes, others are rather fuzzy or even static. Most are rather uninteresting – I got rather bored watching the traffic at the Queretaro Zocalo.
I guess the technology will improve as worldwide bandwidths also improve and obviously some subjects are more suited than others – live cams at the waterholes of African Parks for instance (though some local "control" of the equipment would seem to be necessary to optimize the view rather than just leaving a long range static camera). But I don't think I will be setting up a "Seen live on Webcam" list of WHS just yet.
These links provide an entrée but you will have to search around to find ones
a. Working
b. In the day light
c. Of interest!
This has a number of webcams categorised as "World Heritage" – but includes Mt Fuji which, as yet, is not of course
http://www.goandroam.com/webcams/cams:worldheritageA general Webcam directory with search facilities –Kihzi is there among others (but not working when I looked!)
http://www.webcamgalore.com/EN/Another general site providing search facilities by country and a number of the Webcams are of WHS
http://www.liveworldwebcam.net/day-night-map.phpHere is Old Faithful
http://www.nps.gov/features/yell/live/live4.htmThis Mexican site shows a number of WHS from that country
http://www.webcamsdemexico.com/