Facebook F8 is the conference Facebook holds annually for its engineers and designers, giving them a sneak peek into what's changing on the social network and revealing new products and features. Named after the Facebook tradition of holding an eight-hour hackathon after the presentations, the one-day Facebook F8 event is held in San Francisco and is hosted by Facebook founder Mark Zuckerberg, with keynotes, developer sessions and announcements rolling out plans for the next year.