Having an account with Facebook provides you access to new friends, friends and friends that you go way back with. You can share your thoughts, you can share pictures, movies and interests for your friends and family to see.
You can use what they call applications and play games online. Invite friends to your own Farm Ville or Cafe Restaurant and have them join you. Share free gifts with your friends every time they do a favor for you in these applications. Zoo World, a popular application in Facebook, gives you your own Zoo to fill with plenty of animals to choose from. Of course, you have to pay for the animals using the "game money" in Zoo World. You receive money every time visitors come to your zoo. So, if your friends come and visit your zoo, you get paid!
The ability to chat with your friends while playing games, loading up a new photo, sending a message or browsing a friends profile is my favorite thing on Facebook. The website Facebook has it's own instant messaging system that allows the user to chat with their friends while playing a game on Facebook... at the same time!
I recommend this website to anyone of any age. It's great, simple and fun!