Wiki is an awesome tool for working as a group in projects. Students can cooperate on wiki to write a research, a story, a poem, a report, a summary, a retelling, etc. They can also work together brainstorming on a given topic, finding solutions to a problem,etc. It is an excellent tool for student projects in general, and it allows to expand the initial topic by linking new pages in order to develop related ideas that the students want to explore in depth or need to explain.
Checking the wiki http://childrensbookreviews.pbworks.com/ gave me the idea of having a book review project where students can make lists of books they like/dislike or recommend/no recommend and link the titles to a page where they write a short review explaining why.
I also liked the idea of showing off examples of good student work and create students prtafolios where each one of them can post content, having their own student account.