Using Web 2.0 in an ESOL classroom

The latest edition of Reflect, published by NRDC*, contains a practical article on the use of web 2.0 tools within an ESOL** classroom. 
The author Liz Boyden (http://lizboyden.wordpress.com) outlines the tools she uses which include:

Twitter (http://twitter.com) – micro blog i.e. short messages/posts
Tumblr (http://tumblr.com) – multimedia focused blog i.e. text, photos, sound and video files
pbwiki (http://pbwiki.com) – [...]