In 2005, Y Combinator developed a new model of startup funding. Twice a year they invest a small amount of money in a large number of startups (most recently 52). The startups move to Silicon Valley for 3 months, during which they work intensively with them to get the company into the best possible shape and refine their pitch to investors. Each cycle culminates in Demo Day, when the startups present to a large audience of investors. Since 2005 Y Combinator has funded over 550 startups, including: DropBox, Airbnb, Stripe, Reddit, Optimizely, Codecamdemy, Weebly, Hipmunk, Heroku, Pebble, Rap Genius, Omgpop, E la Carte, Twitch TV, Justin.tv, Socialcam, and Exec.