It seems like only yesterday Microsoft’s Steve Ballmer was busy convincing the world that he was not interested in making a bid for Yahoo.

Now TechCrunch has an internal company email that explains why Microsoft today made an unsolicited bid for the company.

It reads in part:

By combining the strengths of our companies, we can deliver an efficient and highly competitive offering for our customers. Our complementary assets will give us increased talent and scale to compete in the markets of search and online advertising, and pioneer new innovations in the areas of video, mobile services, online commerce, and social media.

Well, maybe there’s some good news to come out of Yahoo’s recent poor financial performance after all–Microsoft wants to buy it for $44.6 billion.

Nobody really saw this coming–you can’t count general speculation–so it will be interesting to see how this plays out. Microsoft offered $31 per share in cash and stock, representing a 62% premium on Yahoo’s recent stock price.

As AP reports:

Under terms of the proposed deal, Yahoo shareholders could choose to receive cash or Microsoft common shares, with the total purchase consisting of 50 percent each cash and stock.

Microsoft said it sees at least $1 billion cost savings generated by the merger, and intends to offer significant retention packages to Yahoo engineers, key leaders and employees. The software giant said it believes the takeover would receive regulatory clearance and close in the second half of 2008.