Social Networks
These are programs that combine the best of all the above into one site. You can add blogs, photo-sharing, podcast, or a variety of tools into your own “network” or “space” that you then share with others. The educational establishment hasn't quite decided how they feel about these yet, and our firewall blocks facebook and myspace to name a couple of the more popular ones. This article does a good job of talking about the thorny issues surrounding social networks.
If you are curious, check out:
Ning
A VoiceThread is an online media album that can hold essentially any type of media (images, documents and videos) and allows people to make comments in 5 different ways - using voice (with a microphone or telephone), text, audio file, or video (with a webcam) - and share them with anyone they wish. A VoiceThread allows group conversations to be collected and shared in one place, from anywhere in the world.
Examples: Grades K-2
Grades 3-5
How to: Build a Social Media Cheat Sheet for Any Topic (ReadWriteWeb)