Earlier today Facebook announced the release of their long-rumoured geographic tagging tool, Facebook Places. In a nutshell, Places will allow smartphone-wielding users to ‘check in’ at whatever notable location they happen to be, and share that information with friends on Facebook (who, as per your privacy settings, will either be a very small group or all 500 million+ Facebook users). The history of whose checked in where will become part of the Facebook record for that place, and thus any tagged comments people make in or about those places will become part of, effectively, place history.

While similar check-in services like Foursquare already exist, the huge number of Facebook users means that this has the potential to bring place-based social sharing even further into the mainstream. Indeed, at the Places launch, Facebook has already announced partnerships with many place-based services, including Foursquare, Gowalla and Yelp; check-ins on those services can also become check-ins on Facebook Places in the near future.

Facebook’s unique selling point, of course, will be capitalising on the existing social networks people have established.  Facebook Places will actually allow people to tag friends, much in the way you can currently tag friends in photos. One iPhone user will be able to tag the all of their relevant Facebook friends as they check-in somewhere. While this is certainly very social, it’s also a huge boon to business and advertisers, and raises a whole new raft of privacy concerns.

For businesses, especially small businesses, Facebook Places has enormous potential. Localised reviews and ratings have been popping up all over the web for years, but the reach of Facebook, and the ease of access, will make social commentary of restaurants, clubs and other businesses easily aggregateable and accessible. Facebook have already indicated that Facebook business pages will be able to integrate the related Facebook Place information. While Facebook themselves aren’t immediately releasing game-based tools with Facebook Places, canny businesses will surely take up this data to reward/encourage customers – as the have with Foursquare – ‘10 Facebook Place check-ins and get a free muffin’ will be with us soon. Of course, an inevitable legal battle is also just around the corner: which will be the first business to sue a Facebook user for a negative comment about that place? The divide between expressing an opinion, and effectively reviewing a location, will certainly blur even further.

With all of this new information sharing come massive privacy questions, and questions which in typically Facebook style they’ve deferred to an opt-out mentality: users will be able to chose, using one of those elusive privacy settings, to either disable other people checking them into places, or they can remove check-ins manually, similar to the way folks can un-tag themselves in unflattering photos. By default, though, it seems everything will be turned on, and users will have to actively seek to disable Facebook Places if they don’t wish Facebook to build a history of where you’ve been. It’s worth noting that the New York Times, The Guardian and Mashable all have articles up citing privacy concerns about Facebook Places, before the service is even a day old. It’ll be interesting to see what problems Facebook encounters with Places, but they’ll no doubt do as they always have: turn it on, let everyone try it out, then slowly deal with whatever complaints and protests arise, knowing full well that 99% of users will never leave Facebook for fear of giving up vital social capital.

Initially, Facebook Places is only available in the US (and thus the official Facebook Places page will show you nothing in Australia today) but it’s sure to land here in the near future. Oh, and no use trying to set you privacy in advance: I’ve checked, and I can’t find a way to pre-emptively  disable other people checking me in; I guess I’ll have to remember to do that once the service is activated down under. Update: It’s now possible to opt-out and disable other people checking you in, no matter what country you’re in.  If you want to disable other people’s ability to add you to their check-in entirely, then follow these instructions from Valleywag.

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Update: While it’s pretty clear that Facebook Places is yet another tool to entice advertisers to Facebook, often seen in direct competition with Google, in a move that really highlights Facebook’s desire to challenge Google, the maps used by Facebook Places will be exclusively powered by Microsoft’s Bing Maps.

Update 2: Facebook Places went live in Australia on 30 September, and it took only hours for the first privacy concerns to arise.