Yes, it has happened again. This time, our fabulous C# Community Program Manager Charlie Calvert was good enough to put together a little half-hour-long video of me talking about the scenarios which justify changes to the type inference algorithm for C# 3.0. We've already made some interesting changes which will make it into the beta version, and there likely will be further refinements to the algorithm as we see how it works.
The video is here.
I shall also likely be blogging about these algorithms over the next few weeks when I find time to turn my developer notes into blog posts.