Ask HN: How do you keep track of your network?

As I meet more and more people I'm looking for a way to keep track of things I know about people so that I can stay in touch with them and stay more personal, but I don't have the best memory.

Do you use any tools/ methods for keeping track of everyone you want to stay in touch with? Of course I use LinkedIn and Facebook, but those don't let me say "Remember, Ryan is working at Yelp, is great at design, and has a cat named Tum-tum".