Now that we are all the beneficiaries of hindsight, of course we expected SketchUp to be released for free. Otherwise, what would have been the point of acquiring it, right? :-)

With that analysis out of the way, let’s look at the more interesting product launch yesterday, at least from a strategic perspective — 3D Warehouse. SketchUp Free is bait for us to feed 3D Warehouse, a content capture system for Google Earth, which in turn is an embryonic digital representation of Earth. So far, so obvious.

But 3D Warehouse is not a unique product. Rather, it is the latest member in a special class of Google tools, whose other members include Google Earth Community, Google Base and Google Video. Emphatically not in this class are Google Search, Images, Desktop and Book Search, for example.

What’s the difference? The first class contains tools for letting humans preëmptively attach meaning to new content being added to the web. The second class consists of machine tools for trying to divine such meaning ex post. Clearly, the first kind of tool is easier to build, and more accurate too. Google rightly prefers that new content join the web fully formed semantically, as it were.

Google wasn’t around when HTML took off around 1993, so it had to come by later to devise algorithms that find the gems in this inchoate mass of information. But Google is around today, as whole new kinds of content gain currency — map layers, 3D objects, video — and it is trying to enforce a new semantic order by offering to host the content in return for some user-generated metatagging, which Google can use for more refined ads ahem search results.

Nowhere is this compact between content contributor and Google more evident than when you try to “Share with Google Earth Community” from within Google Earth. Google will reject your contribution outright if you have not made sufficient effort to describe it:

Upload a video to Google Video and there too you are prompted for metadata. Same goes for Google Base (“Google Base enables you to add attributes that better describe your content so that users can easily find it”) and now 3D Warehouse.

I hadn’t expected this turn of events. When Google Earth launched 10 months ago, Google Earth Community (GEC) was a well-trafficked but niche bulletin board, where Keyhole enthusiasts traded overlays and placemarks. Not being a bulletin-board kind of person myself, I assumed that GEC’s usefulness would soon be eclipsed by reams of enthusiastic content sites, with KML and KMZ files growing wild on the internet, and Google Search cataloguing them ad hoc, as best as it could. The conventional web model would take hold, in other words.

That’s not what happened. Instead, Google tightened the integration between GEC and the client — by giving GEC content pride of place in permanent Google Earth layers, and also by encouraging the categorized submission of new content from within the program. GEC use and membership exploded. As a result, I’d wager that the majority of static KMZ files today are hosted by a google domain.

3D Warehouse intends to repeat this success with 3D objects, stored in SketchUp’s original SKP format and also as KML when georeferenced. All this content is made available to the end user after being thoroughly described by the content creator. From Google’s perspective, this is simply a much smarter way of building the semantic web.

Nor does Google have to worry about the persistence of this content, as it gets to host it. A lot of web content has a habit of disappearing through neglect, which makes Google Search inefficient. Now, instead of the directory pointing at the content, the directory hosts it. This affords Google a measure of control over it — for example, Google can more confidently expect the content to be there to place ads against.

But this control also brings with it the responsibility not to be evil. (Yes, a clichéd sentence, but still true.) Google implicitly acknowledges this by not introducing Gmail and Blogger to China, because it might then have to make unsavoury choices of the kind Yahoo! has made. (More on Google in China in this very well-balanced article by Clive Thompson in the New York Times Magazine last weekend.)

I can think of several situations where content on GEC or 3D Warehouse might irk Chinese authorities sufficiently to pressure Google. What if somebody decided to plonk a fantasy Falun Gong temple in the middle of Tiananmen square? What if somebody makes a georeferenced model of the Chinese man facing down the tank in that iconic image? How about a placemark collection outlining the week’s largest rural protests? Would Google undertake to keep such content out of China? What if China wanted to know who placed it there?

I have no reason to suspect that Google would do anything untoward in such a situation, especially after Yahoo!’s PR fiasco, and besides, people are free to host their content elsewhere. But this brings up another issue: If the majority of a content type is to be found on one proprietary database, with preferential links to an endorsed content browser (e.g. base layers in Google Earth) how does that affect ease of access for other players, including content creators and other search engines? And if Microsoft is going to create a competing virtual Earth, with its own proprietary content capture system generating ad revenue, aren’t we heading down the road to 3D web Balkanization? And is that really a good idea?

I’m not saying that we are going down that road. But one way in which we can make sure we don’t is by focusing on interoperability and open standards as early as possible in this game. The HTML browser wars were not pretty. I wouldn’t want to repeat them in 3D.