After 18 years of hosts files on Windows, I was surprised to see this in Windows 7 build 7100:

# localhost name resolution is handled within DNS itself.
#   127.0.0.1 localhost
#   ::1 localhost

Does anyone know why this change was introduced? I'm sure there has to be some kind reasoning.

And, perhaps more relevantly, are there any other important DNS-related changes in Windows 7? It scares me a little bit to think that something as fundamental as localhost name resolution has changed... makes me think there are other subtle but important changes to the DNS stack in Win7.