Bitbucket is a distributed version control system specially created for professional teams. Unlike centralized version control the copy of repository available regionally. So, it decreases dependability on the central server. Suppose you need the central server to store your code you can store in bitbucket repository. The collaboration also allowable that your teammates can other distributed system like Git and Mercurial along with it.
Bitbucket is available for free of cost as well as minimum cost based on the requirements such as the number of teammates and time period. For continuous service, you can become the account holder on this site by Sign up with the email address.