How does Facebook sharing feature works

Could someone explain me how does sharing website content on Facebook(Facebook sharing feature) works? I know that there are several ways how to share info on Facebook(with 'sharer', 'like' button and so on...) by adding some html or javascript to webpage but how does those features know which content to share? For example, when I click on "Share" button, a pop-up window appears, containing the title, some introduction and even picture from the page I were at. How does sharing features get that information?

The second question: I have noticed that some sharing features doesn't support url's with multiple paramaters anymore(I'm using "Like" and "Share" features for sharing articles from my website, but the content appearing on Facebook is incorrect(some default webpage info)..probably because some parts of url are missing and its impossible to found the right content). Which sharing feature would work for my website if I'm using url's like http://ift.tt/1AJRtjm(with multiple parameters as I mentioned before) and how to implement that feature? An example would be great.