Similar to social networking and so on, discussions boards and groups, often found on social networks, are groups of likeminded people discussing common topics of interest.

I would for instance go to a discussion board or group on the topic of making money at home and participate in the discussions, not missing the opportunity to market any/all of my sites while i'm at it. Likewise if Revlon for example have just released the greatest lipstick since creation you might want to visit a discussion board or group on the topic of fashion and beauty and maybe drop a couple of witty lines about the marvelous new Revlon product and where they can check it out (http://laboutique.synthasite.com/