It was announced by Facebook last August 25 that they are taking steps to improve the News Feed of its users by reducing the number of headlines that trick users into clicking on them by having incomplete information or cliff-hanger type of headlines (also called click-baiting).
First off, why do websites do click-baiting? For one, some websites use this as a strategy to increase traffic count to their websites. The cliff-hanging and incomplete headlines normally encourage a user to want to read more. Increased traffic to the said website can translate to more advertising revenue if the user also ends up clicking on an ad unit while on the said website. Also, more clicks on Facebook meant the content is kept on the News Feed for a longer period of time, thus encouraging even more people to click on it. In a way, this type of click-baiting post exploited the existing Facebook algorithm by keeping a piece of news/content artificially relevant and in the News Feed without spending for advertising.
Facebook is using a two pronged strategy to put an end to this practice.