The popularity of social media has grown by leaps and bounds just within the past few years. According to Facebook, there are 500 million active users! This is fertile ground for companies to market their business. Many businesses have already taken advantage of Facebook, as well as Twitter, marketing. You can look at a variety of businesses (i.e. Coca-Cola, Pepsi, Dr. Pepper) and see that they have Facebook and/or Twitter sites. BrianSolis.com has an article that talks a little about the amount of users who use social media sites as well how much spending consumers do online.

Facebook and Twitter users spend 1.5x more online than the average Internet user