Interesting classroom management software that is using the social networking model to make classroom commnications stronger. It is in Beta, so I encourage teachers to check it out to see if it adds anything to your classroom environment.
Use your twitter or facebook feeds to create a newspaper to really maximize your PLN. Paper.li links to posted links, and puts them into categories.
Similar to PostPost for Facebook. Check out this great example: http://paper.li/ITLynda
If you have a classroom twitter account this would be a great way of organizing all of the classes tweets into publishable 'paper'