[kelnos]

That depends on what you want out of the "distributed" aspect. If all you care about is offline access to the repo, and like the fact that everyone's checkout is effectively a backup of what's on the central server, then centralization doesn't really take away from the distributed nature.

Even if you consider the SPOF-y nature of something like GitHub, more savvy git users will realize that if GitHub was down for an extended period of time, they could push their repo somewhere else that's public, like Bitbucket, or their own server, and keep working and allowing other people to collaborate. And for shorter downtime of the central server (where you might feel like setting up an alternate is too much effort), everyone can still get work done, they just can't collaborate as effectively until things are restored.

[comex]

That works for the repo, but not issues, pull requests, wiki pages, permissions, or any other services GitHub provides. None of those work offline, and while there is an API that can help with migration, doing so still requires setting up a totally different system, and there is no natural backup on every developer's machine like with the repo - you have to do it manually while the origin is still up. (Not that GitHub is likely to disappear anytime soon, but all things will end someday.) Which is unfortunate because it seems like a missed opportunity: it's certainly possible to implement all those things in a decentralized manner, and some projects have tried, but so far with little success...