I'm disappointed, but not with O'Reilly.
I hate M$ more than any person I know, and I hate their practices even more than I hate their crippled software. After 3 years of M$-- before which I ran GEM and CP/M-- I banned Gates from my home in Apr 1992. I purchased Coherent, then discovered Yggdrasil. Years later, I divorced a girlfriend because she believed I should permit an M$ laptop into my home.
Having described myself, I will direct my disappointment at most of the responses to O'Reilly's .NET statement.
O'Reilly has dedicated a great deal to the Open Source movement. They have advanced the movement more than most of us. I admit that O'Reilly is a corporation, and I confess general trepidation towards corporations and their far-reaching agendas, but O'Reilly's rationale seems justifiable. Isn't Open Source about sharing ideas? Making use of what we know?
Knowledge is power, and O'Reilly empowers us. I don't suggest we follow any entity blindly, even Raymond, RMS, or Torvalds, but we should take what they're offering and use it to advance the movement.
Simply being on a bandwagon does not imply we're helping that wagon move. O'Reilly helps it move.