Instacart raised $210M [1] at a valuation of $2B+ [2,3]. Also see the WSJ's Billion Dollar Club [4]

[1] http://www.sec.gov/Archives/edgar/data/1579091/0001579091140...

[2] http://techcrunch.com/2014/12/05/instacart-2b-kleiner/

[3] http://bits.blogs.nytimes.com/2015/01/12/instacart-a-grocery...

[4] http://graphics.wsj.com/billion-dollar-club/

Machine Zone (YC W08)

Source: http://blogs.wsj.com/digits/2014/07/16/newest-hit-game-maker...

Twitch.

Heroku, maybe?