Dalton Caldwell, who once worked at SourceForge, blames the ad-supported business model as the underlying reason Sourceforge sucked[1]. The users were the product and the real customers were the advertisers no matter how much he and his coworkers wanted to believe otherwise. He credits GitHub's straight up reliance on just user revenue as the key to the quality of their product.
We've all been duped into thinking that ads give us things for free. Sourceforge and all other ad-supported sites are not only not free, they are costing us more than if we just paid[2]. We users neec to hear Maciej Cegłowski[3] exhortation, "Don't Be a Free User"[4].
I can't wait for the day when more people realize that entire web is being held hostage by advertising and a web without ads would be to today's web what GitHub is to Sourceforge.
[1] http://daltoncaldwell.com/an-audacious-proposal
[2] https://news.ycombinator.com/item?id=8585237