User blog comment:Dopp/Technical Update: Feb 28, 2012/@comment-13301-20120303151003/@comment-3091914-20120305225046

Don't worry, the sharing menu is loaded upon the first time you tap the share icon, so if you don't tap it it won't generate any additional load ;)

Also, it's not using FB/G+/Twitter external JS, it's just plain HTML links, so no loading unused JS :)