All the details are not known, including his reason for running. On the surface it seems dumb, but on the other hand there is such a thing as common sense, and even if he didn't know much about Facebook, discussions like the one we're having and how it could lead to him being captured again have doubtlessly reached him by now.
My immediate guess would be that he was somehow offered an oppertunity to escape with a virtual guarantee he wouldn't be recaptured, for whatever reason. Half the point of him posting on facebook might be that hes POed about his incarceration (rightful or not) and knows that the police are never going to be able to get him... like say if he's in a country that doesn't allow extradition currently, or was passed a "get out of jail free" card for some reason (working with other authorities or what not) and he's having a laugh that the police didn't get the memo (which has happened even in the US, people getting released from prison early for whatever reason and then the police freaking, while things have gotten better discussions between differant levels of prisons, and differant departments like police and corrections are not always what they should be).
It will be interesting to see what happens. Any way it goes, my assumption would be that he's not as dumb as many people think, and simply very confident about his position.
I'd also laugh if Facebook DOES give over his information, he was an early release of some sort (making light of the situation and the inabillity to correct it), and then he sues them.