Correct me if I am wrong, but is there are only adsense units inside of the threads? I think the ad placement is good. What if the user setting show newest posts at top? Would the ad unit be there or still on the original post?
since you use vb, search for adsenseexperts forum, the guy running it has a vb forum and provide some of the best ad placements for forum I've ever seen.
not bad at all just if you can change the colour for your ad unit to get higher cttr dont add more ads units i hope the best for you
Placement is ok, and as a forum most people won't stay on homepage for long time so you'd better set up the site and show ads on most threads.
Ads' placement is ok ,and I agree with StoneWilson, most people don't stay on homepage too long because they are surfing around to find what they want and then they move onto something that interest them.