Hacker News Reader

Tobi Lütke of Spotify - http://tobi.lutke.com/

Dalton Caldwell of App.net - http://daltoncaldwell.com/

Jack Groetzinger of SeatGeek - http://jackg.org/

Eric Koester of Zaarly - http://ekoester.com/

I wouldn't necessarily add Dalton to the category of "Successful" just yet. Although he is a great influencer and a great technologist.

ZING (too true though)

minor edit. Tobi is the founder of Shopify, not Spotify.