I think it depends on the venue that you use to find employment and how you use it. Facebook is a great tool if you are middle aged and have all of your college and local friends available to network to. Linkedin is good too.
All of these social networks are good depending on what use you have for them and what you are asking of your friends and those you know casually. I've used networks to find jobs or let the word get out that I was looking with some success.
However, if you use your social network page to rant and it is filled with garbage it could work against you.