Online multimedia development environment allowing interaction (by voice, text comments) linked to shared resources (e.g., images). The following description is from the "about" page - 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.
Create and share presentations on the web (free for small space)
Introduction to Social Media (a prezi presentation)