Google announced they have added some search refinements to the various Google search properties. The additions include past hour, specific date range, more shopping sites, fewer shopping sites, visited pages, not yet visited, books, blogs and news. To see them yourself, do a search on Google and then click "Show options" at the top.
Danny Sullivan goes through these changes in detail over here, so I won't bother with that.
Some Google users are a bit taken back and confused by the changes. One frequent Google News searcher was confused in a Google News Help thread as to where certain features were, when in reality, they were just moved. But overall, I think the additional filters and refinements are useful.
Jaime at Google posted a thread at the Google Web Search Help thread asking for comments and feedback on these new changes.