The up-and-coming version control system git has begun to prove its mettle outside of Linux kernel development. The Ruby on Rails community has embraced it wholeheartedly with many core projects migrating to the system recently. The climate has become right for businesses to spring up in the wake of this adoption.
Public repositories like the ones at repo.or.cz and Gitorious have been around since the earliest releases of Git, but they come with their own limitations that project participants may or may not want. You must make your code public from the beginning. You have limited types of access on many of these services and your project may have a strictly limited amount of storage for your code.
Recognizing the need for more flexible options, github was created. The service provides fully supported options for all sorts of projects--both open and closed source. There are pricing levels that fit the needs of open source projects and larger companies. The company has provided a very slick web front-end to the system with extras like a wiki and integrations with the ever-popular Twitter and Basecamp services. Github also recently open sourced much of the code that is used for these integrations so that other projects and companies might expand on their work.
It will be interesting to watch how this new business unfolds. SourceForge has long been the preferred place for open source projects to share their code and host their SVN repositories, but their lack of support for the new kid on the block has left them lacking for many. Google Code is also becoming a large player in this game and it remains to be seen if it will support git. Without a doubt, git brings a lot of convenience and flexibility to the version control party, but there is still a lot of uncertainty about whether github or its ilk can unseat the dominant players in an already small market.