Back in January, I explained and described Facebook’s foray into making a search engine called Graph Search, and how it had the potential to turn things upside down.  Beneath the search box exterior lies an alluring rich mine of user information, which marketers would sell their grandmothers for, information which has been pretty much volunteered and offered up by Facebook users themselves in their profiles.

Now Graph Search has become even more powerful, with the news that all public posts on Facebook, will be fully searchable via the Graph search engine. That means that every public post you ever made on Facebook can now be brought up on the monitor for all to see.

Private posts (such as ones to your friends, or your lists and closed groups) will still remain private and out of the reach of Graph Search (at least for the moment anyway – who knows what plans Mr Zuckerberg has for the future?), but the public posts?  They are now fair game. Throw in the fact that Facebook is now mimicking Twitter by allowing Graph Search to recognize hashtags, and you’ve got yourself a search function where you can find out a lot about someone, perhaps more than they would like.

But before we get to the bad part, let’s look very briefly once again at what’s good about Graph Search. The bottom line is that Graph Search has a huge amount of personal information about you, and your Facebook friends. That means that whatever search term you put into Graph Search is going to be based on real-life accurate information, information which is relevant to you. Do you want to know which of your friends shares your taste in TV shows? Ask Open Graph. Do you want to know if any of your friends have been to a restaurant in New York?  Ask Open Graph. Do you want to find people from college who attended the same classes as you, in the same year as you? Yup, ask Open Graph. Google can only dream about having this kind of interaction and knowledge with the user.

But it goes without saying that access to this kind of information is a double-edged sword. Employers and divorce lawyers are probably celebrating as we speak, as anything remotely compromising is now going to be seen by anyone who knows what to ask Open Graph.  Were you tagged at a party where you are chugging from a vodka bottle, while flashing your bottom? Or are you perhaps leaving status messages showing that you are at the ball game every weekend with the boys, followed by a bar crawl?  Then look forward to not getting a callback for that job interview you really want, and you can forget about winning your custody battle at the divorce court.

Of course people will say that it’s your own fault, that you shouldn’t have revealed yourself too much online, that it was set to public for everyone to see. But let’s be honest. When you are interacting with friends online, showing them photos of where you’ve been and what you’ve done, are you always looking to see if you have set the right privacy setting? It’s very easy to overlook it. And it doesn’t help that Facebook sets the privacy level to “public” by default, as they obviously would prefer it that way for Graph Search to work. So the onus is on the user to remember to change it, and to continually check that it hasn’t been changed back.

But I will let you into a little secret. If you would prefer that your posts become private, and therefore out of the reach of Graph Search, there is actually a setting buried inside your Facebook account privacy settings, which allows you to switch all public posts to private in one fell swoop. There’s no need to individually switch each one to private, which would be time consuming and extremely tedious (although you might come across some amusing past status messages that you had forgotten about). Obviously Facebook is not advertising that it is there, and to find it yourself, you would have to be examining each privacy setting in turn to come across it (and how many people are likely to take the time to do that?). So I am here to tell you about it. Look upon it as a public service announcement. You’re welcome.

To make things really easy for you, here’s the link, which will take you directly there (obviously you will have to log into your Facebook account as well). When you’ve clicked that link :

look for “Limit The Audience for Old Posts on Your Timeline“. Then click “Limit Old Posts“. You’ll be asked if you are sure. Obviously you are, if you’ve come this far, so click the button again. It’s all done. All of your public posts are now private.

You can test if it has worked by going to your Facebook profile page, then pressing the gears icon next to “Update Info” (at the top, to the right of your header image). Pick “view as” and then “public”. You will now see what your page looks like to the public.

There will still be other things there, such as the books you like, and the movies you’ve watched. You will have to go into those sections separately to change the privacy settings to “private”.

Let us know in the comments if you will be switching your privacy settings. Or do you not mind being indexed in Graph Search?