Microsoft is bidding to acquire Yahoo! at $31 per share. The letter sent to Yahoo!'s Board of Directors in interesting in several ways from a collaboration/communication/content strategies point-of-view.
First, the letter notes, "...the combination allows us to consolidate capital spending." While mentioned within the context of online advertising, the consolidation of Yahoo!'s and Microsoft's datacenters would give Microsoft a huge backend for its ongoing push into software and services on the enterprise side.
Second, the letter says, "You should also be aware that we intend to offer significant retention packages to your engineers, key leaders and employees across all disciplines." One of the recent jewels that Yahoo! acquired is Zimbra, and if the Zimbra folks stayed around and allied with Microsoft's research into useability, Microsoft would gain a very interesting asset. Of course, given the Java and open source parts of Zimbra, Microsoft could shoot it as well, so who knows.
On a business note, a pattern seems to be emerging here. In the case of FAST Search, Microsoft had its eye on the company for awhile, but waited until a FAST execution/strategy stumble depressed the stock before bidding. I would contend the same happened here. It's classic Business 101, but it highlights the fact that timing is part of the equation.