I've seen a few comments on the XMLHttpRequest working draft that we published along the lines of "Microsoft not invited" which are quite surprising to me. Perhaps the people writing these posts aren't familiar with the W3C process which allows any member organisation to join any working group at any time. Everyone has paid for the right to join and the announcement of new groups is made very clearly. Microsoft are a very active member of the W3C and participate in lots of groups. Why aren't they in this one? I don't know, but there are often many reasons why members don't participate from the start such including being too busy or just not seeing it as a priority. The W3C patent policy can also cause problems for members who sometimes need to go through all kinds of legal wranglings to sign up to its terms. It could be any or none of those reasons, but saying they weren't invited is just plain wrong.