How does social networks (like Facebook, Twitter, Myspace, and ETC.) effects peoples lives? Is it good or bad?

[Kikey46]

I've always check my Facebook account. And it occurs to me that practically billions of other user do the same everyday, and not just for Facebook. There's Twitter, Friendster, Myspace, and ETC. This doesn't just apply to ordinary civilians. Celebrities have made a special page on well themselves. And these special pages don't just apply to celebs, there's companies, restaurants, food, music, and anything you can think of, can get more publicity via Facebook. Maybe I am just talking about Facebook. But I always wonder how BIG is Facebook, and how other social websites have made an impact to our lives? What effects will happen to us and our next generation?