Mark Drechsler, @markdrechsler has a few great presentations concerned with Moodle on Slideshare.net. Here’s a good one that covers the comparison and integration several web2.0 tools into a Moodle classroom (http://www.slideshare.net/mark.drechsler/web-20-tools-and-techniques).
My favorite slide is 19. Mark discusses attributes of the Moodle blog and wiki. At first glance, I was not a fan of either (full disclosure, I’m still not a huge fan of the Moodle blog at it’s current iteration). But the wiki has grown to be one of my favorite features of Moodle in general. It doesn’t do grades, but it does allow for extremely easy group based collaboration and rapid resource development (both huge benefits).
The wiki can be used in all sorts of fashions, but even with beginner Moodlers it’s simple enough to get a hang of. Here’s a video I created that shows how to utilize a Moodle wiki for M4T (http://www.integrating-technology.com): http://www.screencast.com/t/okEN4PjuzV