Facebook. Here's mine. I also have it in my website list to the left. I head about it for the first time from my friend Josh (former co-worker who deserted us for Egypt and is going back home to Canada soon). Then Emma finally sucked me in by inviting me to her facebook. I can't remember, but I think you have to sign up in order to view someone's page, but it's a lot of fun. You will never imagine some of the people you can find on there! It will even automatically send an invite to the people in your address book who are already members, then they confirm the invite and you are friends!
I know, I know, like you need another site to keep you on the internet (that is just what I was thinking), but this is a great way to keep in touch with people in a rather non-committal way. You don't have to make posts all the time like on a blog. You can leave a quick message for someone on their "wall." You can add your work and school details and it will let you know who else from your college or place of employment are members. Cool!
Sign up and add me as your friend. Then I can finally see what you are up to rather than just knowing you are lurking on my blog and not leaving comments! :)
Oh, and if you are from American Expats just let me know who you are because I may not connect the name and the screen name. I don't want to just add any old weirdo as a friend. Just the expat ones. ;)