I am using the offical php facebook sdk and I am pulling data about the current logged user by doing a simple:
$data = $fb->api('/me', 'GET');
now, $data contains a whole lot of stuff among which there is, as you might well know an id ($data["id"]). My question is: given a certain user, how unique and immutable do you reckon this piece of information is? Do you think it can change over time?
It’s unique and won’t change (according to the whole of FB API docs, but it is not explicitly said).