This is not my recollection, at least at the time. I remember meeting with one of the SourceForge founders and being a little star struck. SourceForge was a huge deal at the time and we totally felt like we were the underdogs in that arena. Perhaps later they got more desperate, but in 2008, SourceForge was the 900lb gorilla.
2013 is when the binaries had malware included although even in 2008 they were guilty of having 5 download buttons due to excessive and unpoliced inline advertising with only one of those buttons being the holy grail that linked to the download you actually wanted. Choose wisely.
I completely forgot about the absolute gamble that was "which big green button is the actual download button this time" when using SourceForge and Tucows back in the day.
They did indeed host quite a lot of stuff, and it was undeniably popular as a place to get your binaries hosted free of charge.
But at the same time, is it being used as a source code repository? A lot of those projects don't show the CVS/SVN features. And sourceforge never hosted the biggest and most established projects, Linux and Gnu and PHP and Java and Qt and Perl and Python were all doing their own thing. And pretty much every project visible on that page had its own separate website, very few projects hosted on sourceforge exclusively.
SourceForge was the upstream source of truth for a huge percentage of small apps bundled by various distros (and BSD ports etc). Even when the upstream maintainers just uploaded the latest tarball to SF and didn't use their hosted VCS, just the hosting was a major boon to all of the tiny teams and individual maintainers of FOSS projects.
