This service is fun:
Have you ever wondered whether you’re related to anyone in the 23andMe database? Now, you can connect with them and begin exploring how you’re related with a new, free tool from 23andMe called Relative Finder.
Check it out and see who in the 23andMe community shares your DNA here: www.23andme.com/you/relfinder/
Communicating with my cousin from the US, I never knew I have :).