The jsonp method causes older browsers to use a ton of memory if you leave the browser window open for a long period of time. You'll see that there's a whole b

The jsonp method causes older browsers to use a ton of memory if you leave the browser window open for a long period of time. You'll see that there's a whole bunch of script tags in the dom that aren't cleaned up. Given the way people use facebook & how many old browsers still exist, this is probably the reason facebook decided against it.