It would be interesting to see the mailing list activity for open source projects. If a project has a good community and being actively used, the mailing list would have a lot of emails. If the mailing list was started several years ago, but no recent emails would show a dead project.
You could also measure how many responses a post gets. If it receives none = poor community that doesnt help out. If it has many = good community that tries to help users.
Anyway, thanks for your site; it is really good and fun :D