The newer projects on the MS backed OuterCurve.org (formerly Codeplex.org) all use either an Apache or BSD license.
I suspect two reasons for MS accepting the Apache, BSD, and MIT licenses:
1) the terms of those license are not very onerous and let the end user pretty much do as they will. This is very important to a company like MS that has a lot of code and needs to be paranoid about subjecting themselves to patent suits.
2) Joe Briefcase has no idea what-so-ever what the "MS-PL" license is - no name recognition at all. The Apache/BSD/MIT licenses have been around so long and are so commonplace that they are generally acceptable to most everyone, and most developers shouldn't have a problem using one of those licenses.
> Apache2 is not in the same league as BSD and MIT
From the point of view of a company looking to release proprietary products utilizing the licensed code, though, it's similar to BSD/MIT in a good way: you can do it without problems.
I suspect two reasons for MS accepting the Apache, BSD, and MIT licenses:
1) the terms of those license are not very onerous and let the end user pretty much do as they will. This is very important to a company like MS that has a lot of code and needs to be paranoid about subjecting themselves to patent suits.
2) Joe Briefcase has no idea what-so-ever what the "MS-PL" license is - no name recognition at all. The Apache/BSD/MIT licenses have been around so long and are so commonplace that they are generally acceptable to most everyone, and most developers shouldn't have a problem using one of those licenses.