[eluser]Ollie Rattue[/eluser]
[quote author="WanWizard" date="1290293866"]Why?
Mercurial works as well as Git. And so far, I haven't seen any problems with Bitbucket. And I can't say that of Github...[/quote]
More to do with the community than the functionality. After all SVN does the trick...
I have seldom (actually I can't think of a single instance) got CI code (libraries, helpers etc) from BitBucket but I frequently do from Github. Github is the the go to location for various highly active CI developers. So it seems to make sense to host the CodeIgniter repository there as well.