In a deal that has some experts scratching their heads, Microsoft announced today that it’s acquiring Skype for $8.5 billion.

Reuters’ Bill Rigby writes that, while Skype’s technology was groundbreaking at its height and is still quite valuable, it’s hard to see how Microsoft will manage to get its money’s worth:

Microsoft is hoping that more business users would be willing to pay for Skype if it is integrated with Outlook e-mail, which hundreds of millions of people already use, or that more gamers will pay to join the Xbox Live network if real-time video and voice services are added.

It should also allow its new Windows Phones to compete directly with Apple Inc and Google Inc smartphones, which already feature video chat.

But some investors carped that Microsoft already had the technology to do this, or should have developed it itself, and may soon be overtaken.

Peter Bright in Ars Technica writes that Microsoft certainly has technology it could have developed into the features it’s hoping to get from Skype:

Microsoft’s own software already has considerable overlap with Skype. Windows Live Messenger offers free instant messaging, and voice and video chat. It currently boasts around 330 million active users each month, typically with around 40 million online at any one moment. Microsoft has an equivalent corporate-oriented system, Lync 2010 (formerly Office Communication Server) that allows companies to create private networks that combine the communications capabilities of Live Messenger with corporate manageability. The underlying technology of both platforms is common, allowing interoperability between Live Messenger and Lync. The company also plans to integrate Kinect into Lync to create more natural virtual presences.

Even considering Skype’s paying users, Bright writes, Microsoft still seems to have paid too much.

USA Today quotes IDC analyst Al Hilwa offering some explanation for the high price that Microsoft paid:

“If Skype ended up in the hands of Google, it might have been able to use it to strengthen its ecosystem at the expense of Microsoft,” says Hilwa.

But keeping Skype out of the hands of Google,may have furthered a different company’s agenda, says Om Malik of GigaOm:

The biggest winner of this deal could actually be Facebook. The Palo Alto, Calif.-based social networking giant had little or no chance of buying Skype. Had it been public, it would have been a different story. With Microsoft, it gets the best of both worlds: It gets access to Skype assets (Microsoft is an investor in Facebook) and it gets to keep Skype away from Google.

Facebook needs Skype badly. Among other things, it needs to use Skype’s peer-to-peer network to offer video and voice services to the users of Facebook Chat. If the company had to use conventional methods and offer voice and video service to its 600 million plus customers, the cost and overhead of operating the infrastructure would be prohibitive.

Malik adds that Facebook could also help Skype garner more users and revenue.