I was using IE9 beta till now and installed IE9 RC today. However it starts crashing on 50% of the sites I visit. This also includes www.youtube.com. 

I did not uninstall IE9 beta before installing IE9 RC. Could this be the reason?

EDIT: I have uninstalled IE9 RC and installed it again after restart but that has not fixed this issue. 


Question: Mutually generics
Answer: Another fact to add to Joel's list, one which I found surprising when I first came across it, is that adding a single Cohen real adds a perfect set of reals such that any finitely many are mutually generic over each other. To see this simply consider the trace of a Cohen real on the members of an almost disjoint family and use the theorem Joel quotes about products.