Michael Affronti is blogging about lots of interesting things. He's the Program Manager for, among other things, RSS Aggregation in Outlook 12. His early posts include a good one on "Instant Search." I'm dogfooding Office 12 and that feature is used at least 15 times a day. No more hunting for that elusive email. Just Ctrl-E (the keyboard shortcut for the search box) and start typing.
The speed and power of the new Outlook 12 Search functionality are two of the most noticeable improvements, as we are now able to return sub-second results to the user over their entire mail store. That means we are able to intelligently index and catalog all of your Outlook mail, calendar, contact, and other data types quickly at startup and keep track of new items while Outlook is running, while making a minimum impact on system performance and never interrupting your work.
Check it out.