Knowledge is power (and profit) for Microsoft. Since the MS-DOS era, Microsoft application programs have used secrets about the OS to give their products an advantage. More recently, Google says that Microsoft has been slowing down competing file-search products, making MS's Instant Search appear better by comparison. Following Google's anti-trust complaint to the US Justice Dept., MS might make some changes:
In response to claims that Vista’s “Instant Search slows competing products, Microsoft agreed to give competitors technical information to help optimize performance.