I'm off to India in January for two weeks (that's not entirely relevant here I just wanted to let you all know I'll be sunning myself while you're not), and while doing some random research about jabs I came across a pretty cool initiative going on over there - Social Blood.
Social Blood is a very simple Facebook app, where users register their blood type and are directed to a group for their particular type. In this group, they can post messges asking for blood in an emergency, or help someone else out.
I love the idea of using Facebook as a platform for emergency help. There's not much going on in my blood group (0+) but I'd love to see what the 0- page is like. I've signed up just in case. You never know.