What were you doing Monday? According to Mark Zuckerberg, it probably included using Facebook. He just posted that for the first time, the social network notched one billion individual users in a single day, calling it "just the beginning of connecting the whole world." With that kind of scale, it's no wonder the exec is focused on drones, lasers and satellites to connect the rest of the world to the internet ASAP, because he's got an idea what they'll be logging in to eventually.