This idea is open to some debate, so I thought I'd launch it here. One of the things the hot threads feature shows is that postings of interest may end up in forums you wouldn't expect. As the forums and threads proliferate, I think we will need a way to search across forums and within a forum. That is, forum search should be added to the advanced search page and a search box added to the forums tab. On the advanced search page, there should be a drop-down box of all current forums, and it should accept multiple selections. (by the way, all the advanced search dropdowns should allow multiple selections). Oh, and allow a phrase search, perhaps using quotation marks. Oh, and the search results (individual threads) absolutely have to identify their forums.
Sounds like we're talking real money. Time for the sponsor a feature page?
Now for the potential controversy. I want to be able to search across forums that I don't yet belong to - just as I can see hot threads from groups I haven't joined. I entirely agree with maintaining the join-to-post rule and onlly having groups I've joined appear on my forums tab, but would rather not have to join-to-sample. I guess the searchbox on my individualized forums tab would have options for "search my forums" or "search all forums".
As I write this, I also think we may need a policy on cross-posting. If cross-posting is to be allowed or even encouraged, we might need a mechanism to facilitate it. On the other hand, because facilitating cross-posting could invite abuse, it might be better to have a way to link to a thread from inside a different forum. That too would require controlled access to all forums, not just the one's I've happened to join.
This idea of opening the forums to lurkers might need input from the group administrators. Is there a group specifically for group administrators?