Web 2.0: cool tools

Referring Tools: 
List of Web 2.0 tools for teachers and teaching: Presentation Tools Collaborative Tools Research Tools Video Tools Slideshow Tools Audio Tools Image Tools Drawing Tools Writing Tools Music Tools Organising Tools Converting Tools Mapping Tools Quiz and Poll Tools Graphing Tools Creativity Tools Widgets File Storage & Web Pages Other Helpful Sites
Lenva Shearing
Target group: 
Teachers. Language = English.
Positive elements: 
Tools are classified by technical use, but everyone includes a short description. It is being built by the users (teachers).
Lack of examples.