Everybody knows about the Microspeak term dogfood. It refers to the practice of taking the product you are working on and using it in production.¹ For the Windows team, it means installing a recent build of Windows on your own computer as well as onto a heavily-used file server. For the Office team, it means using a recent build of Office for all your documents. For the Exchange team, it means moving the entire product team to a server running a recent build of Exchange. You get the idea.
Purists would restrict the use of the word dogfood to refer to a product group using its own product, but in practice the meaning has been generalized to encompass using a prerelease product in a production environment. The Windows team frequently dogfoods recent builds of Office and Exchange Server. Actually, the Exchange Server case is one of double-dogfood,² for not only is the server running a prerelease version of Exchange Server, it's doing so atop a prerelease version of Windows!
Dogfooding does have its costs. For example, the prerelease version of Exchange Server might uncover a bug in the prerelease version of Windows. While the problem is investigated, the Windows division can't send email. These outages are comparatively rare, although they are quite frustrating when they occur. But you have to understand that the whole purpose of dogfooding is to find exactly these sorts of problems so that our customers won't!
¹ Despite the efforts of our CIO, the term ice-creaming has not caught on.
² I made up the term "double-dogfood" just now. It is not part of Microspeak.