The Battle of Short & Social continues. While skirmishes have been taking place ever since the URL came in to substitute for IP addresses and complex network directories, the struggle to dominate the territory of Short & Social has been one with many participants — TinyURL came in with hand weapons, Digg brought mortars, but both were soon overwhelmed by the major armaments of Facebook and Twitter.

Now, enter a potentially game-changing air campaign from Google. Dubbed “+1,” the new Google recommendation engine is strafing Facebook from above — with a clear view thanks to the big open skies of search.

Aimed at replacing Facebook’s “like” button, +1 allows users to signal which search results, search ads, and Web pages they prefer — adding robustness to Google’s recommendations, advertising campaigns, and pervasive online presence.

To turn it on for your results, just login to your Google account (or create one if you don’t have one already), then visit their Experimental page and activate the “+1 Button” experiment. It looks like you might need to do this for each browser you’re using, which seems odd. But my three-browser experiment was limited to a Firefox 3.x version on one Mac, a Firefox 4 beta on another, and Safari. The only browser of the three that worked for +1 was Firefox 3.x.

Ironically, +1 launched on the same day Google had to settle a privacy dispute with the Federal Trade Commission. According to the New York Times:

Google agreed to start a privacy program, permit audits for 20 years and face $16,000 fines for any future privacy misrepresentations. This is the first time the F.T.C. has charged a company with such violations and ordered it to start a privacy program, the commission said.

Google has released a slightly saccharin video introducing +1. But it’s an informative video, so the sweetener is worth tolerating:

Some are asking why anyone would click on +1? Also, with your +1 recommendations tied to your Google account, these same people are speculating that this is just the thin edge of a wedge Google plans to continue to push into the social space. I think that’s a safe bet.

How do you get a +1 widget for your Web site? You can’t yet, but Google is taking requests. All you have to do is provide an email address and URL, and you’ll be notified when the widgets become available.

Will +1 be gamed? Possibly. But because there is a match between Google accounts and +1 activity, abuse will probably be detectable and remediable.

You can also “+1” advertisements, much as you can “like” ads on Facebook. Advertisers will certainly appreciate the extra feedback.

Ultimately, +1 is a way for Google to head Facebook off at the pass. TechCrunch underscores how this is a volley in the battle for Short & Social:

Whether they’ll admit it or not, Google is at war with Facebook for control of the web. Facebook is coming at it from a social perspective, Google from a data perspective. But the two sides have been inching closer to one another. Facebook isn’t fully doing search — yet. But their social ad play is also a huge threat to Google. Probably even a bigger threat, since that’s the way Google makes the vast majority of their money. And +1 is a big attempt to keep pace with Facebook in that regard.

The battle for the Web continues, and the partisans are looking more and more alike. For me, that signals that another front is likely to open soon, one featuring a surprising entrant and new terms of engagement.

In the meantime, Google just raised the stakes. By +1.