Our site covers a small widget collecting niche that have mass produced widgets that sell from 2-60 bucks to artist made widgets that go into the thousands. So our articles are mostly made up of artist release notices of a limited run of widgets and news of the acme company's widget line for the year. Sometimes we get the news from the artist and have the only pics of a widget in the works. So when we get the hot news is when we see referals from other forums that are in the same niche.
The niche is made up of probably 98% women that span the whole age spectrum and are located internationally (mostly US). I would say in this group who collect widgets I don't think a lot of them know how adsense works or really cares but it only takes one I suppose. Not to long ago when you asked someone for their personal website odds are a collector would give you a photo bucket or webshots url and a widget creator would give you a yahoo group url. That is still pretty much true today but now more people are starting sites on freewebs and a few going with paid hosting and a tld.
Since the question of another forum came up, I thought it might be good to look at competition as well, which would be other niche sites with adsense and forums. Right now in the niche there are only a couple of other sites in the niche that use adsense. None of the sites that have adsense overlap in use or content so it would be better to do a banner exchange than to try and get them booted from adsense.
Next we have competition with similar uses which would be other forums none these profit from adsense. Some are freely hosted and the host inserts adsense on the page but the owner just gets a free site. Most are not direct competition, because of a regional focus which is across the pond from us, probably 75% of those are non English. Or it is a specialized forum concentrating on a specific section of the niche.
After you throw those out your down to one other forum that also covers all aspects of widget collecting, competing for the same user base and competing for the same direct banner advertisers.