"Given pre-condition #2 (traffic), Facebook Like buttons are going to be everywhere. All of the top sites will have them, and most of the medium-sized sites wil

"Given pre-condition #2 (traffic), Facebook Like buttons are going to be everywhere. All of the top sites will have them, and most of the medium-sized sites will too." Wrong. All the medium-sized sites will have it, and all the >= 2nd place large sites (bing, retailers that aren't amazon) will have it. All the top large site will have their own systems to push.