Did you even know Facebook has unilaterally decided to share all your data with anyone it pleases?

In the space of just over two years, Facebook has gone from being my favourite website to being one I hardly ever visit and that I am seriously contemplating leaving altogether.

When I opened my Facebook profile in 2007, I saw it as a way of sharing content with friends: people I knew in real life and with whom I wanted to interact privately, secure in the knowledge that what we shared was not available to the hoi polloi. The use of real-life names and the symmetrical nature of the ‘friendship’ relation on Facebook contributed to making it different from other social sites. These were factors that helped it consign Myspace to the dustbin of Internet history, to the point that the media don’t even carry stories about how Facebook has kicked Myspace’s backside any longer.

Facebook turned this policy on its head in December when it unilaterally made certain parts of users’ information public whether they liked it or not. It’s just decided to carry this one stage further, with its Like button, that users can use throughout the Internet if it’s installed, providing they log in to Facebook through a dialog box in order for their presence and activities to be shared with their Facebook friends.

That’s something I can live with: there are times when I may want to share a link on Facebook rather than on Twitter or Google Reader, because it’s something I only want to share with my friends. I don’t need a special Like button to do this, though: you’ve been able to share links on Facebook ever since I started using it, and even my least-technologically savvy friends seem to manage to copy and paste a link in the appropriate Facebook dialog box, so the whole ‘Like’ button buzz seems to me to be rather pointless.

Or perhaps it isn’t. Gagaom carried a story pointing the finger at something Facebook are clearly hoping most of you won’t have noticed (Mark Zuckerberg threw it in as a one last thing during his f8 keynote):

Facebook also introduced a way for certain sites to push this further than everyone else. Three carefully chosen launch partners — Microsoft’s Docs.com, Yelp and Pandora — have access to what Facebook is calling instant personalization. This is a powerful, inventive and creepy tool that the company hopes to extend to other partners but is testing the waters with these three first. […]

Instant personalization means that if you show up to the Internet radio site Pandora for the first time, it will now be able to look directly at your Facebook profile and use public information — name, profile picture, gender and connections, plus anything else you’ve made public — to give you a personalized experience. So if I have already publicly stated through my Facebook interests page that I like a musical artist — say, The Talking Heads — the first song I hear when I go to Pandora will be a Talking Heads song or something that Pandora thinks is similar.

As things stand, there is still a way to opt out of this creepy new move by Facebook, aimed squarely at exploiting its users’ naiveté to justify its surreal $25bn valuation, although they’ve kept so quiet about it that you may not have noticed (I didn’t until I looked for myself). Head for your privacy settings, and you’ll notice there’s a new setting at the bottom euphemistically called ‘Instant Personalization: Control how select partners can personalize their features with my public information when I first arrive on their websites’.

Clicking on this brings up a screen where you can opt out of having your entire Facebook details shared with anyone Facebook chooses: but the nag reminder above shows how hard Facebook tries to claim it is somehow enriching your browsing experience when all it is doing is breaching your trust and exploiting you to increase its valuation at the expense of your privacy.

Facebook’s disrespect for its users’ privacy and, as such its breach of their trust has been so cynical and creepy that it’s brought me close to the point where I may close my account altogether, or at least significantly downgrade my use of it. And you can certainly rest assured that you won’t find any Facebook ‘Like’ buttons on this website: if you want to interact with me on Facebook but we don’t know each other in real life, there’s a dedicated page for that.