When you first sign up for Renzulli, your child will fill out a personality profile of their interests. Then the database will recommend various lessons and sites he/she may be interested in. For project based learning, students seem to enjoy the resources found by this site that may otherwise be missed by conventional search engines (IMO).
I haven't used the site extensively and wonder if the children can collaborate with one another.
I may be mistaken, however, the Univ. of N. Carolina has started a forum/blog type of site where audio/visual posts are able to discuss various topics. Can't remember the name of it at the moment :S
