During the week the Open Source Initiative organization approved two Microsoft licenses as OSI compliant, the Microsoft Public License (MPL) and the Microsoft Reciprocal License (MRL). (See PC World article for more.) From all reports, both sides (OSI and Microsoft) played nicey-nicey and after a few changes to the Microsoft licenses they sailed through without any shouting. That wasn't true externally as some wanted to make a beef "in principle" for allowing capitalistic Microsoft to have any license they could legitimately call open source, more-less licenses that are OSI approved. Sort a fox in the open source hen house argument. But Microsoft played this wisely and to their benefit.
The MPL in particular is really a very open license. You can modify, distribute, commercialize and charge for modifications. It doesn't skirt the edges of open source but rather embraces it. Microsoft has had three licenses (one wasn't submitted) as part of their Shared Source Initiative, a way for Microsoft to dip it's toe into the world of open source.
So whether you love Microsoft or love to hate Microsoft, all of us have to give them their due for playing by the rules and cooperating with the OSI. Is this the proverbial "slippery sloap" or has Microsoft had a mid-life open source change of heart? Have no doubt, Microsoft is doing this because it benefits them by at least starting to play in the open source sandbox. I've viewed it as something that's inevitable but was surprised at how cooperative Microsoft was in getting these licenses approved. Where and how broadly they use the MPL and MRL only time will tell but for now they at least have their Open Source Players Card and keys to the open source locker room.