As a slight improvement (I hope), today I added links to specific Forum topics from the relevant site pages.
Often interesting background stories are discussed or queries answered on the Forum, that are useful when preparing a trip to a WHS. This way they are not 'lost' anymore among the many forum posts.
So far I only added topics that are about a specific WHS, I don't know if it is worthwhile to go any deeper.

See for example: http://www.worldheritagesite.org/sites/ashanti.html

I like that idea, anything that makes the site more useful will be great. How are you picking out the relevant posts, is it just trawling through the forum for them, or is there some (semi) automated way of doing it?