How many successful reasonably known startups run on windows?

[artilheiro]

I am just curious, Google, Twitter, Facebook, Yahoo all run linux. How many do you know use Windows?

[aditya]

Myspace does too: http://highscalability.com/myspace-architecture

[a2tech]

Well-Stack Overflow, Serverfault and all the other things Jeff Atwood is involved with runs Windows.

[hga]

I've read that eBay's Java front end runs on Windows (and still runs on it due to general cluelessness; their capacity management problems have to do with the latter).

[gus_massa]

Writely used Windows and C#. (Google bought it in 2006, now it is Google Docs.)

[katovatzschyn]

Does Microsoft count?