According to Firebug: roughly 250 KB is transferred, half of that is lazy loaded (after DOMready, I suppose) and it looks like the biggest file (75KB) is from Google+. All scripts uncompressed (not un-minimized) weigh about 740 KB.

Makes me wonder if it's the difference between a different language being compiled to minified Javascript vs. minified Javascript.

~790k (min) in IE8