What's wrong with dashes?
http://news.com.com/8301-10784_3-9748779-7.html - Underscores are now word separators, proclaims Google
It didn't say that there was anything wrong with dashes. Instead they're saying that they'll accept dashes in addition to underscores.
I'm kind of surprised they didn't parse that before. I thought they were even parsing stuff like IAMTHEEGGMAN into word parts, with no separators.
But then again, this seems to be for actual .html document names, and that's not all that important a word compared to the document's title and H1 header.
Sounds like a minor tweak.