FB.api - are users unique?

So 开发者_Go百科in my app, I do this:

FB.api('/me', function(response) {
  alert(response.name);
});

This gives me the users name IF they are logged into FB through my site. Now, is there a way I can get a unique ID for them as well? That way everytime they post something on my site, I can store their post along with their FB name AND Id, and then I know which posts they have made in the past when they are connected to their FB through my site.

You can use response.id to get the Facebook Users unique id.