DAVID BYRDEN
Facebook's "Like" button, and its other Social Plugins, don't just send data to Facebook; they also connect your web page to Facebook's "Social Graph".
Ths graph is Facebook's biggest asset; a huge network of things. It was originally just a network of people, but now Facebook want to add all the things that people like to talk about.
If your web page is about something, you can add that thing to the Social Graph by putting a "Like" button on your page. But you need more than just the button. Facebook won't 'scrape' your page and try to read the text like a search engine would; it's actually very difficult for computers to understand plain text. Facebook require you to put some carefully structured "metadata" in your HTML code, so that your page can be automatically linked to their Social Graph.