I know people who use social networks every day to advertise their business and they are very successful. I think that if you are a business owner, affiliate marketer or a blogger, you should be signed up for all the major social networks. Twitter, Facebook, Linkedn, Youtube, etc. The key is to promote on these sites daily so that you gain a following. On Twitter you want to get a bunch of followers. On Facebook you want to gain friends. On Linkedn you want to update your profile as much as possible and on Youtube you want to gain subscribers. I love social networking, it is very effective.