The group of WPMU rockstars at UBC's OLT just whipped up a fantastic new plugin for administrators of a WPMU site to get a feel for the growth of the community. It generates a graph to display growth in numbers of blog posts and comments over time, and uses the Google Data Visualization API to let you interactively define data ranges to be graphed.
Here's the growth of UCalgaryBlogs.ca graphed for the last 2 semesters:
Another fantastic job by the OLT blogging platform crew. Now, to just add users and pages, and it'll be perfect... ;-)