Chris,
upon closer examination, could it be that the implementation of ISearchable is a bit off. If i search (making use of the dnn search facility) my forum for a word i know should give a lot of hits, and it only gives me the latest post (that also contains the searchword). I know for sure that search worked fine in the 3.10.04 version.
I looked at the code in ForumThreadController.vb, and noticed that you filter on LastIndexDate. Thats a cool feature, as it will keep the number of items that are returned to the search indexer down. What i did was set the LastIndexDate in the moduleSettings to a very low date, so all the items would be indexed again, and yes... after that reindexing indexes all posts now, and the rss feed is filled again too!
Might it be an idea to expose the LastIndexDate somewhere to allow for easy reindexing if something is wrong with the index? Up untill now, i always assumed that to completely reindex a site, i could clear the SearchItem table, and just do a complete reindex. If modules keep track of LastIndexDate themselves (which is good in itself ofcourse), "power users" like me are completely in the dark why things don't work as expected.
Anyway, to get back at the topic of this thread, i now have an rss feed of all latest threads in my forum (I only display the top 10 items in the feed). For me this is a workable solution. If you want to have a look at how it looks now, see here: http://www.apollo-software.nl/Forum/tabid/163/Default.aspx
Cheers,
Erik