Ask HN: What startups use Express.js or Node.js for their primary product?

I’m lead dev at Tesults.com and we use this stack. Are you asking about VC backed up companies however? Tesults is bootstrapped and not massive yet so may be there is a reason it’s not used more widely which means I’ll discover why and have to deal with it soon :-) Although I hadn’t heard it’s only used for smaller scale projects, is this anecdotal or is there data?

Interested in the answer too

EDIT: I actually use node for my primary product which is a mmo game but it's too soon to consider the organization as a start up.