I get some of my traffic from forums but most of it, (unfortunately) comes from my Adwords advertising.
I get fair traffic to my occult sites here on DP, much better then I ever thought I'd get. It is also important to keep in mind that when building links from a forum/community stand point it's important to keep in mind that it's not just having a sig link, it's also about delivering high quality posts that make people want to look at your sig. There are also other advantages to posting in forums, and it's not just sig links. You can squeeze out other links in posts if you are on topic and the post is relevant. Though keep in mind that you should place the community first and your links second. Doing that will help make people want to click. I give other tips here: Forum Link Building tips (it's not just your signiture!) Q
Here's one interesting spin you can take..... instead of focusing on VOLUME why not make your sig extremely specific and targeted? This way you get higher quality traffic?
It's pretty tough unless you put specific tags to your signatures. Like for example, traffic from dp would be linked to "yoursite.com?track=dpsignature" - traffic from a florist forum signature could have "yoursite.com?track=floristsignature" (And then you'd need to store these visitor amounts to database and analyze that data). Although I would simply prefer checking overall traffic from forums.... Like, you naturally could simply check referral stats from your web traffic analyzing tool.
i think it's related forum category and your site category. if both of them are related you can recieve traffic from forums
Forums are good for direct traffic. It will take you alot of time to post in each forum though and also make each site and keep them updated. Could be alot of work.