YouTube users are now uploading three days’ worth of video to the site every second — a whole 24 hours more than the site had last year. To celebrate its 7th birthday, Google’s video-sharing site released all-new metrics about itself, including its new upload numbers as well as the fact that subscriptions increased 50 percent in the past year. Another cool fact? The site logs 3 billion hours of viewing time per month. The site also released — what else? — a YouTube video timeline of its history, documenting its rise from the garage of YouTube founder Chad Hurley in 2005 to more recent statistics such as the record 30 million views that the Kony 2012 video got in just one day. The news comes as YouTube pivots to try and change its format to be more focused on its channels, which are gaining viewers and subscribers. The most-viewed channel on the site, run by comedian Ray William Johnson, has seen its videos viewed 1.7 billion time and has 5.4 million subscribers. The appetite for channel programming is growing, with YouTube sinking money into promoting its original content from established names like Machinima or celebrities like Felicia Day. The site has even started courting advertisers with network-like upfronts, to secure advertising for shows before they air on the Web. Yet even smaller channels continue to grow at fast rates, with channels such as BlackTreeMedia, a channel focused on African American programming, announcing Sunday that it had hit half a billion views. In remarks at this year’s Consumer Electronics show, YouTube Vice President Robert Kyncl predicted that 75 percent of all channels will be born on the Internet in the next 10 years, and that 90 percent of Web traffic will be video.