The reason why GitHub has become so popular is due to the fact they put code and developers first. Surfing to a repo doesn't bring some overview or ads page.
Opening a repo actually show useful stuff for me as a developer. The source is there together with an optionally inlined README file, rendered with popular micro markups.
Then add the ease of forking and you clearly get something people really like.
This style of presentation isn't of course for everybody. But GitHub chose to target developers above end-users.
GitHub could have been "SVNHub" or "hghub" for all I care, the technology is secondary in this case (but close behind).
I agree with you that the technology is secondary, but one of the biggest things that I like about Github is that navigating through source files is always very fast.
I hate having to go to a source control site where it's not immediately obvious where to get to the source, or even worse, where it takes multiple seconds for a page to load.
With Github I can flip through all the source files to see what I'm looking for without having to bring the repo down locally. The same thing is also very useful to me when I want to remember how I did something in some project but don't have all my source with me. If navigating between files was slow or cumbersome, I don't think they'd be nearly as successful.
In a way, you're right. However GitHub's model is subscriptions fund the free yet small open repositories whereas SourceForge's model is advertisement (I can't find a way to on SF though).
So naturally, GitHub had to appeal for subscribers. While for SF, I always thought ads was stupid due to the educated demographic that would likely have adblock.
Opening a repo actually show useful stuff for me as a developer. The source is there together with an optionally inlined README file, rendered with popular micro markups. Then add the ease of forking and you clearly get something people really like. This style of presentation isn't of course for everybody. But GitHub chose to target developers above end-users.
GitHub could have been "SVNHub" or "hghub" for all I care, the technology is secondary in this case (but close behind).