In the meantime I think everybody knows that Bill Gates left Microsoft. It is not uncommon at Microsoft that if somebody leaves that he or she sends a mail to people they know like "My last day at Microsoft" saying goodbye (and telling you how you can keep in touch if you want). It was strange, however, to get this mail from Bill Gates (without the point how to stay in touchJ).
There was an internal meeting to say goodbye to Bill. If you are interested (some quite touching scenes are in there), here are the videos: