Why Microsoft is Going Open Source

All is explained here (well, not all, but a bit.)

Behind and Beyond Halloween

The publication of the first Halloween memo in 1998 was a pivotal moment in the history of free software. For the first time, it was clear that internally Microsoft was worried by this new threat, despite its outward-facing bravado and rhetoric.

Of course, there was no confirmation from the company that the memo was genuine, so there was always a theoretical possibility that they were faked in some way, although the internal evidence seemed overwhelming. But now, Groklaw reports, we have official proof of their genuine nature. The posting also offers an interesting meditation on how all this feeds into Microsoft's current attempts to "go legit" with the ECMA standardisation of its Office XML formats.