Why Did Google Buy DocVerse

There's a lot of speculation on various blogs about Google's acquisition of DocVerse, a startup founded by former Microsoft employees to enable co-authoring of MS Office documents. Most of the discussion has focused on the potential of Google integrating DocVerse into its apps portfolio, but given the chasm in terms of feature/functionality between Google Apps and Microsoft Office, it doesn't seem that the idea of a MS Office and Google App user co-authoring a document is going to be feasible anytime soon.

Instead, is it possible that Google aims to position DocVerse as a hosted alternative to SharePoint for workgroup collaboratation, delivering a Wave-like functionality that integrates with Microsoft Office as a separate service from its Apps? The universe of Microsoft Office users is a massive order of magnitude larger than those using Google Apps, or who will use Google Apps in the next few years, so why not challenge Microsoft's two big growth engines - SharePoint, and the forthcoming Office Live Workspace to provide a real-time collaboration capability compatible with Microsoft's desktop suite?