SOCIAL NETWORKS > Losing Their Cool: The Downside of Expanding Hot Social Networking Sites

Facebook, a social networking site known as an online meeting place for college and high school students, is opening its doors to more people in an effort to grow beyond its current nine million registered users. The problem: The move could be risky if it blurs the company's focus and dilutes its brand.

Social networking sites often connect people within certain demographic groups -- such as students, business people, independent music fans or twenty-something urbanites -- using tools such as chat, uploaded pictures from users and online diaries.