Facebook or Twitter (or other social networking sites). The post "5 Ways to Learn..." at JEA Digital Media has some great suggestions for getting online and learning about the sites that our students use. While this post was written with journalism teachers in mind, it applies to all of us. Do what you can, but get involved online. It opens whole new worlds!
photo from http://www.flickr.com/photos/61963330@N00/617650945/