Google has published it’s own social network (Facebook alternative) called Google+ (plus.google.com). The networks looks absolutely great and you need to be invited to get in (untill they get out of the beta version, later it will be opened to everyone). Google+ also allows image uploads and has friends tagging feature. Thanks to that you can now upload these images from TagYourFriends.com to Google+ and tag your Google+ friends.
Tag Your Friends on Google+