Paul Graham is a programmer, writer, and investor. In 1995, he and Robert Morris started Viaweb, the first software as a service company. Viaweb was acquired by Yahoo in 1998, where it became Yahoo Store. In 2005 he and Jessica Livingston, Robert Morris, and Trevor Blackwell started Y Combinator, the first of a new type of startup incubator. Since 2005 Y Combinator has funded over 800 startups, including Dropbox, Airbnb, Stripe, and Reddit.