Ping.fm is an online service that let's you post to almost any imaginable social network site simultaneously. You can also use it as a way to update your blog in different blog platforms (Blogger, Xanga, Wordpress.com, etc.)in a snap.
There's also a multitude of ways to use ping.fm:
- Yahoo Messenger
- Windows Live Messenger
- Pingfire.us(a Firefox extension)
- ...and many more