Catch up on Fast Company 's series following the startup factory Y Combinator ahead of Demo Day (happening now in Mountain View).
When startup incubator Y Combinator launched in 2005, founder Paul Graham was a little-known entrepreneur advocating strange notions about how to grow a startup. In retrospect, those weird ideas proved revolutionary and YC currently has a network of some 700 portfolio companies with a collective valuation of $30 billion. Now, with 29 year-old Sam Altman leading YC's next evolution, we've been following his Winter 2015 startup class with a series of weekly stories, culminating with a print feature coming up next month. What will Altman's expansion efforts mean for YC and how Silicon Valley works in 2015? Read the series so far here: