The version control software market has evolved a lot since Bitbucket began in 2008. When we launched, centralized version control was the norm and we only supported Mercurial repos.
Github was launched in April 2008 [1]. Bitbucket is harder to find, but was definitely around by June 2008 [2]. Mercurial vs git was definitely the defining difference between the two initially, though the Rails ecosystem exploding onto Github made a huge adoption difference. git being faster + built in support for rebasing was big was well.
