Even though Nike don't seem as hot on it these days, I love the Nike+ website, and always upload my runs to it.
I'm also a nosey bugger and like looking at other people's running schedules, pace etc. But so far none of my actual real-life mates have signed up to it.
If anyone fancies adding me to their friends to compare and spur each other on, I'm "Swiss James".
Cheers!