Recent University of Virginia graduates Steve Huffman and Alexis Ohanian were on a train back to Maryland last April when they got the call that changed their lives.

The two buddies had come to Boston to apply for a summer program that would give them living expenses while starting a new website collecting popular news stories recommended by the site’s visitors. It would be called Reddit.com.

But the venture firm that had offered to pay their expenses, Y Combinator in Cambridge, had considered 227 startup proposals – and Reddit hadn’t made the cut.

So Huffman and Ohanian began the trip back home to Charlottesville, Va., dejected but determined to prove Y Combinator officials wrong.