I also remember SourceForge fondly, before the ad infested thing.
Specially, I remember not "getting" Github at some point. Bitbucket had mercurial support, sourceforge had SVN, and all the Cool projects lived in SF (I'm talking mid/late 2000s).
The first time I navigated into a github project and just saw the code three I was puzzled. (SF was centered on the project/product while GH focused on the code.
Hey, I also remember Launchpad and Bazar, and adding an individual new source to my apt. Launchpad had something like CI before everyone from what I remember.