When seeing "team sites", I immediately knew this is intended to compete with SharePoint. If not immediately, then surely at some point in the future.
Sure, it used to be JotSpot. But the MS attack seems still obvious.
SharePoint is growing massively in recent months, but its a fairly monstrous thing. Think "corporate IT". They want "customizability", even though in the end its going to cost them more than the initial licenses.
Anyway, Google is now supposed to be a Big Software Corporation, so it needs to compete with other Big Software Corporations in every area. (Though I always thought they were a Big Advertising Company.)
Of course, I haven't used either service, so I might be talking out of my ass.