well its depend what you use it for. when i came to states, i lost contact with all my friends, some had changed their e-mail address and some got busy in life. now with facebook i know what my friends are doing, who got married, who got kids n stuff. my profile is hidden from public and only my friends and family is on my list. i only log in once a week and check whats going on with my friend's life. its very useful thing but ofcourse you can use it for wasting your time too. Its up to you.