Web 2.0 for Learning

Of the thousands of Web 2.0 applications which have been introduced, which are appropriate for use in learning situations? What makes an application more effective for learning than another? Do you have success stories to share... [more]

Of the thousands of Web 2.0 applications which have been introduced, which are appropriate for use in learning situations? What makes an application more effective for learning than another? Do you have success stories to share regarding a web 2.0 application and learning? Are some better for formal learning situations and others better for informal learning situations?