Following the Rackspace cyber attack in December, the company has issued a final update on exactly what happened, and you can read this at https://status.apps.rackspace.com/index/viewincidents?group=2
Perhaps one of the most important paragraphs is
Of the nearly 30,000 customers on the Hosted Exchange email environment at the time of the attack, the forensic investigation determined the threat actor accessed a Personal Storage Table (“PST”) of 27 Hosted Exchange customers. We have already communicated our findings to these customers proactively, and importantly, according to CrowdStrike, there is no evidence that the threat actor actually viewed, obtained, misused, or disseminated emails or data in the PSTs for any of the 27 Hosted Exchange customers in any way. Customers who were not contacted directly by the Rackspace team can be assured that their PST data was not accessed by the threat actor.
Email data that was locked is being made available (generally as downloadable PST files) and Rackspace has said that it’s move from Hosted Exchange to its Office 365 platform will be permanent.
It will be interesting to see how this has affected customer loyalty, or when they will seek to start charging for the Office 365 environment, which so far has been free of charge for those affected.