Tis the season to shop around, and while you're out there buying gifts, sometimes you have to splurge on yourself. That's what IBM is doing, which announced that it has entered into a definitive agreement to acquire DemandTec, a cloud-based analytics company, for around $440 million in an all-cash transaction. IBM is hoping the acquisition will extend its Smarter Commerce initiative by adding cloud-based price, promotion, and other merchandising and marketing analytics to its portfolio.