Facebook’s new Graph Search (currently in Beta testing to limited users only) will eventually allow anyone to search data across the platform and precisely identify people with common interests. For example, if looking for a a companion for a lunchtime snack you will be able to instantly search for “friends who work at my company and like sushi.” Or a weekend trip to a new city could be improved by searching for “museums my friends have been to in Paris”. Basically, almost any semantic search query you can type in 112 characters or less will soon be enabled.

It’s not yet known how users will embrace this new feature but there’s no doubt this creates many new possibilities to identify specific tribes on the world’s largest social networking platform.

Thankfully, even though you cannot opt out of your data being used in Graph Search, the search results presented  will respect each user’s privacy settings at the moment the search is conducted. If your privacy settings state that your activity on Facebook should be restricted to friends, then so too will be the ability to search your data.

I suspect that this may lead to more Facebook users locking down settings to reduce the risk of their personal data falling  into the wrong hands. If you haven’t done this already, now would be a good time. And go back through your Activity Log (not your Timeline) and delete anything that you do not want to become instantly searchable.

So, while today many people think it’s relatively harmless to ‘Like’ a Facebook page about recreational drugs or their religious affiliations, once Graph Search is fully enabled, those choices may come back to haunt. Human Resources Managers, for example, could be forgiven for wanting to identify “people who work at my company who like weed.” Already, there are some fairly dramatic examples cropping up showing how this search functionality could be abused, including “Mothers of Jews who like Bacon” or “Married People who like Prostitutes.”

The greatest hope, perhaps, is that the introduction of Graph Search will make Facebook users more aware of how their data can be used, making them more selective in choosing what to ‘Like’ and associate themselves with across the social network. And that, ultimately, is what Facebook wants too.

And to all those companies that have built their Facebook fan base on short term incentives and prizes I’d urge you to be particularly attentive. If many of those ‘friends’ you’ve attracted turn out to be the sort of people who will ‘like’ almost anything online, irrespective of how wholesome or appropriate it is for your brand, the public relations challenges ahead could be damaging.