When I have a dependency problem ( usually some arbitrary version of a lib that needs to be compiled and linked ) it's much easier if the project is on Sourceforge where I can just go and read down an index to find the appropriate release, which is not necessarily the latest one, and hit 'Download' to receive a nice bz2 which will de-tar into a buildable structure.
At that point in time I don't want to fork the project, or engage socially with other developers, or pick through tags to piece-together a checkout that will link against the dependee. I just want something compilable ASAP.
Perhaps Sourceforge could find a niche there, organising the bazaar of projects on the Git* sites into something sane.