According to Henry Blodget at Silicon Alley Insider, he's hearing more rumors that Microsoft is poised to buy Limelight Networks, a CDN (content delivery network) from which Microsoft recently licensed technology, apparently to build their own CDN.  According to Blodget:

Microsoft has recently settled on a single P2P architecture to support its Windows Live, MSN, and other online businesses (the company previously had three separate systems). Our source believes Microsoft also wants to own and operate its own CDN architecture and sees Limelight as a quick solution to the CDN piece of the puzzle.

While rumors can often be just that, regardless of whether they're coming from "insiders" or not, Microsoft is in the process of building its own CDN, according to a report by DataCenterKnowledge.com

"Right now we're actually building our own edge network," Debra Chrapaty, Corporate Vice President of Global Foundation Services for Microsoft, said in a presentation at a recent conference for web architects. "We're going to put nodes all over the world that we can leverage a little more broadly than we could by using a partner."

It would seem to make some sense to just buy the company and quick start the process of building a Microsoft CDN, but we'll have to wait and see how this plays out.