Highlights for the investor visa: - The investor must be coming to the United States solely to develop and direct the enterprise - The investment must be substantial. It must be sufficient to ensure the successful operation of the enterprise - must have the capacity to generate significantly more income than just enough to provide a living to the investor and his or her family, or it must have a significant economic impact in the United States
I'm not sure if a YC funded founder would be elegible, but seems hard
Rough guide to application : 0.5-1.0 inch thick.
You also have to maintain control of your company, ie you can never give away more than 50% of the equity in the company - and that will be prohibitive when seeking investment.
The company is thus limited in it's ability to fundraise above a certain point and an exit is impossible without the founder leaving the country.
http://en.wikipedia.org/wiki/E-3_visa
I can imagine that incorporating a company in the US and then having that company sponsor you would be a valid use of the E3. Once the company has an LCA to prove a US resident can't do your job (requires some hoop jumping and waiting around), it's super easy to get the E3. For a really young/small company you'd probably need to go to some effort to prove that the company isn't simply a vehicle to get the visa for a foreigner.
I had an E3 and left of my own volition without applying for an extension. I tend to get a couple of minutes of extra questioning when going in to/transiting the US now, based on their assumption that I obviously want to return to live/work there, having experienced their awesomeness in the past. I know another person in exactly the same situation.
(edit: changed LMO -> LCA. I was confusing Canadian and US terminology)
eg. You would still need a US co-founder. E1 or E2 may be a better visa to use if you don't have a co-founder.