Apparently, Microsoft are looking to spend a cool few $$ on a start-up called Xobni. This is a neat plug-in for Outlook that replaces the To-Do bar to totally improve the user experience and change the way you use Outlook. http://www.xobni.com/ is worth a look, check the video out too.
There’s some analysis of your mailbox which creates a new contact profiles from the content of emails only, and then creates relationships between your contacts. The searching is improved also. I like the email analytics which shows the volume of email and time of day profile of messages to/from a contact profile. I know a few people who’d hit this off the scale ;-)