No "mistakes were made", or "We're sorry if you're unhappy about this issue" or any of the other Non-apology apologies[1]
[1] https://en.wikipedia.org/wiki/Non-apology_apology#The_Perfec...
Bringing up this point might be a better thing to close with, after you communicate what happened. This is the real world, miles from best practices.
They really need to provide a few more details as to why they believe the database was compromised, not much of an explanation offered here.
To me that read like an attempt to shift a bit of blame and some subtle framing.
Just a wild guess here, but perhaps the same person who compromised Linode's customer service portal was also trying to see if any of his targets were reusing their Slicehost account credentials in the forum?
They can only be upfront and show how well they respond to the situation including mitigating future security issues.
To the forum, or to their management site? Only the forum was compromised, and heading to http://forum.slicehost.com/ takes you here: http://www.rackspace.com/knowledge_center/content/slicehost-...
However, if you used your Slicehost forum I.D. and password in other places, including any Rackspace account, we recommend that you change those I.D.s and passwords. In fact, the next time you attempt to access the Slice Manager, you will be required to change your password. If you use the same password for the forum and for your Slicehost account, and you also use an API key, we recommend that you consider changing the API key as well.
