Sourceforge seems unable to evolve because its business model is stuck in Web 1.0: bring as many visitors as you can and throw as many intrusive ads as possible in front of them before they can get what they wanted in the first place and leave.
As far as the terms themselves, O'Reilly was talking about a change in focus from software to data... http://twit.tv/floss73
From that angle, then: SourceForge is a great place to download installers, while GitHub is a great place to get the nitty-gritty details about making a bit of software.
