We eat our own Dogfood in Exchange and talk about it often so we wanted to share some very special insights with you on the process. What is Dogfood? It's a slang term we use for using our own software, including alpha and beta varieties internally at Microsoft prior to shipping our products, in order to validate scenarios at scale, in a real world environment with real users who need to be productive. This is an important part of our ship cycle since it not only allows us to work out production-level bugs or issues but also validate deployment guidance, documentation, support paths and align scenarios with other partner products such as Windows, Office, SharePoint and Lync.
In the Exchange world, this means that we deploy extremely early version of Exchange in production starting with a few mailboxes, hundreds of mailboxes, then working with MSIT to move thousands of mailboxes - and eventually deploying to the entire company.