Page CTR around 1.35% this month but my Individual Ad CTR is much less.. around 0.15%.

I personally feel that the key to getting decent Adsense revenue from a forum really isn't by concentrating on the CTR, but concentrating on getting unique hits.

Often I search for something (usually a "how to" something) and a forum such as this one shows up in the results because one of the regulars posted the information I was looking for.

In other words, getting your forum posts indexed and ranked will increase your CTR. The problem is most, if not all, forums suffer from issues such as duplicate content (multiple url's accessing the same post) that may prevent decent rankings for the content of your forum. Your site may get ranked well, creating an opportunity for more regulars and repeat visits, but the actual content in the forum may not be ranked good, meaning only the regulars see it.

Just my 2 cents.

my forum ranks pretty well in google.
and revenu is going up as well with ctr's that go from 1 to 2%. I said it before, use forum soft that delivers a simple forum not one with all th ebells on it and you already have won half the battle.

My average forums CTR from January 1, 2006 through today is a dismal 0.21% (on 12 million pageviews). I've tried all sorts of stuff to get it higher but nothing has worked. It's mostly ad blindness on forum pages, since those are usually your regular visitors, and many times they click through several pages just reading.

The key here is to show ads only to guests right after the first post in every thread. That's by far the best way to attract clicks.

My CTR has been real good and steady. My problem is the eCPM has been rather low and keeps on falling.