I just heard that the technology behind Tacit's expert location system has been bought by Oracle. I've heard a lot of good things from users of their product, and they were true pioneers in pulling information from large email stores.
This seems like a smart move by Oracle. Their Beehive collaboration suite integrates email, IM and document management, so it's a perfect environment for a service that relies on data mining. They're still struggling to convince the market that they're a contender, and Tacit adds a unique feature to their system. With Microsoft boasting that Sharepoint is the fastest-growing product ever in the history of the company, this is obviously a space they want a piece of.
I must admit I'm disappointed that Tacit's no longer an independent company, I was hoping to see them blazing a trail for email data mining. After this and Contact Networks' acquisition by Thompson, there's not many standalone businesses left in this field.