Until August <a href=" http://www.buscadichos.com/essay-global-warming-short ">saving nature essay</a> The social network attempted to answer that question at a special event at its Menlo Park, Calif., headquarters on Tuesday, explaining how the system has moved from manual knob-turning during the feed's early days (they used to increase or decrease the number of photos or status updates you'd see based on anecdotal feedback from users) to the systematic algorithm that determines what you see today.