About.me is a personalised home page which makes it easier for people to find you, and see your activities on the internet - or at least those ones you choose to share. It's a reasonable tool - the kind of thing that would be good to add to a business card or in a .sig file for example. They have now added in a people search as well. Interest, place, organisation or name are the options given. You get a list of people who match your search returned to you, and you can then access their page to view the information that they've made available.
It's a nice tool - it listed 677 librarians, and it's easy to add in extra terms to filter down to the people that you want. It's not comprehensive, because it only lists the people that it knows about, and that's limited to what they decide to say about themselves, but within those parameters it's worth a look if you're trying to find someone.