If you are open source software user you should definitely check out www.ohloh.net.
Ohloh provides data about:
*Project data – code base, growth team, license, estimated cost
*Developer Information – activity, checker info, comparisons and languages
*Broad Trends – Language use, application use, geographies
*Stack Information – complimentary applications, suggest applications (not yet implemented)
Some key features:
*Ohloh support multiple repositories (CVS, Subversion, and Git) per project.
*If some developers on a project have used different name spellings in the source control system, one can combine these names together using contributor aliases.
*Project popularity is calculated by Ohloh using the Inlinks count from Yahoo Site Explorer at (https://siteexplorer.search.yahoo.com/)
*The stack-up feature can give better information with respect to the actual software usage. In past, some O/S analyses considered ‘download’ as an indicator of usage of the project
*The project provides the lines of code (LOC) for mark-up and code.
*It also provides the estimated number of resources (not impressive thus not recommended) if the project has to be start from scratch. The estimated project cost can be then calculated for each project, based on the resource salary/compensation. Basically, it uses the traditional COCOMO model to calculate the man hours.