Matt Warren talks about what happened to ObjectSpaces, WinFS and why [MS] is going with LINQ to SQL as sole ORM product in Orcas wave. Very interesting read I have to say and kudos to Matt for such a revealing post. It actually reveals many (odd looking) decisions. They remain odd but at least one can understand the reasoning behind them.
Anyway, one piece of the puzzle is missing. He doesn't mention Entity Framework with a single word. Perhaps in next post we'll read about EF's story (hint for Matt).