A great many open-source projects and companies have started on SourceForge.net. There's currently about 176,000 registered projects and 1.8 million registered users. Sure, not all of them are active or essential software, but if you want to build an open-source project, it can be a great place to get up and going. You may not go to SourceForge directly very often, but if you download open-source software, it's often sitting on SourceForge servers.
If there's been one knock against them, it's that their infrastructure is just average, not the latest-greatest. That may be changing. This past year they've added wikis and other functionality that helps with collaboration around projects. There's also Marketplace, which allows you to buy and sell related products and services.
Continuing in the vein of bringing new technology and functionality to its army of open-source users, today SourceForge is announcing implementation of OpenID. OpenID is an open-source single sign-on technology that allows an individual to jump between online accounts without re-entering a username and password each time. That's handy. Even better, they're doing it the right way: They're starting by accepting OpenID log-ins, not providing them. This follows nicely in the spirit of the open-source community. Many big name companies have declared OpenID support, but often only as Identity Providers. Meaning, they're happy to extend their user log-ins, but won't accept OpenIDs created elsewhere. What's open about that? (Google's Blogger is a major exception.)
From the SourceForge.net Community Blog: "It's bringing us back in touch with fresh Web (2.0) technology; as a decentralized open-source standard, it's a perfect fit for us--it allows us to streamline more user interaction and participation with our site, and hopefully more for the whole OSS community."
For more information, go to: http://alexandria.wiki.sourceforge.net/OpenID