Yes, signature files can drive targeted traffic to your sites when used effectively.

Basically, they are classified ads.

That means all the rules of 2 step advertising apply

1) Advertise something the forum members are interested in. You can’t make much money advertising hamburgers to vegetarians

2) You have to give people compelling reasons to click your links. HINT: use something free your ideal prospects wants right now! I call that BAIT.

3) Capture their name and email address and deliver the BAIT with your Autoresponder. I use Traffic Wave  and Aweber.

Visit promotingonautopilot.com for more tips on converting forum visitors into customers