I have been with Microsoft for almost 4 years now, all that time working with Exchange. I started out as a support engineer of Exchange mail flow and eventually moved to administration support where I now mentor support engineers as a Technical Lead. In admin support we handle all the issues related to stores, recovery, services, directory, and all the other heavy duty stuff that makes Exchange tick. As a tech lead I get involved with a wide range of issues so nothing I see really surprises me any more. I believe one of the best ways to learn about Exchange is to see and do, so I always have a few labs handy to reproduce scenarios and experiment with product behavior.