Microsoft is actively colluding with the NSA. No software company has been quite as collaborative with the NSA as Microsoft has, e.g. in providing direct Skype access. But this is not the story which the media tends to tell; instead it focuses on companies like Facebook and Google.
Microsoft offers back doors at the operating systems level, not just the Internet/communications level; the NSA as a whole has come to share a bed with Microsoft (even staff intersections exist) and this technology giant, Microsoft, also receives payments for these abuses of privacy. e.g. from the CIA, based on clear disclosures (leaks).
The following articles cover examples of some of the ways in which Microsoft actively spies on people, directly (for its business interests) or as a proxy for governments.