Not many Microsoft employees dare to publicly refer to WinFS as a black hole. Matt Warren does in this blog post. He gives us great insight into the origin of LINQ to SQL and how it managed to survive. He ends with:
So, for the sake of LINQ and the customer in general, we took up the OR/M torch officially, announcing our intention internally and starting the political nightmare that became my life for the next three years.
I briefly talked with Matt at PDC05. It was pretty clear already that he had had a big role in the development of LINQ to SQL even though the public presentation was done by Anders Hejlsberg. His blog is pretty quiet, but Matt is much more active on the MSDN Forums answering questions about LINQ to SQL.