Short bio: Computer Scientist, FOSS supporter (read more)
Tux Machines (TM)-specific
There are many services that will host your project's source code, mailing lists and bug trackers. While very few of these services charge for their services, most of them are built on proprietary software. Worse, some of them have started adding adverts for proprietary software in their mailing lists, or refusing projects with certain free software licenses.
For a while, Sourceforge was released as free software. When VA Software decided to make it proprietary, two forks of the software were created -- Savane, and GForge. Development of Sourceforge has moved along quite a lot since then, and the version of Sourceforge now is quite different from the free software projects that are still being maintained. One additional reason to avoid Sourceforge is that they include advertisements for proprietary software in their mailing lists, so simply using a mailing list on Sourceforge is helping to promote non-free software.