If you load the forums like.... 1 at top one at bottom one in every page with topics forums catigories and one on the post screen and one over quick reply option you will be set. If you do the above and have about 2,000 uniques in a month you will make $120.00 Atleatss thats how it was for me. I know theres the factor of page veiws per user but generally speaking you should be good.
Hm. Numbers vary widely. I have almost have this number of uniques per DAY and I am still not making this much per month.
No, I don't. Yahoo Ads are not very well targeted, especially on forums. I get ads that are not related at all to the posts.