`dig Twitter.com mx`

I must be missing why this is important, shocking, or otherwise news-worthy.

I imagine a lot of companies use Google Apps, regardless of size - it's a reliable service that requires very little in the way of setup and a lot in the way of functionality.

If Twitter offered email, documents, calendars or competitors to any of the other core Google services then I could understand why this might be interesting. IMO this is no more significant than Twitter using Microsoft (or Apple) operating systems.

So... http://mail.google.com/a/twitter.com ?

This in known since that time when Twitter got hacked.