Tumblr reached the milestone on Friday and to celebrate, the main dashboard has been decorated with confetti. Tumblr has been around since 2007, but just experienced major growth in 2010. Most recently, Tumblr’s growth has been tremendous. The site had passed 6.5 billon posts in June. This means that they’ve added the remaining 3.5 billion posts in just the last three months. Tumblr has reached many milestones in the past year, including passing WordPress in total blogs, and is on track to finish a huge funding round that would value the website at $800 million.