[ig1]

If you're from a country which has a visa waiver program in place you don't need a B1. The visa waiver is usable for tourist or business purposes with business purposes being those defined under a B1 visa.

If you come from a country which doesn't have a visa waiver program in place then the B1 is your only option I believe.

[pclark]

the problem with vwp is you can only stay 90 days and you really need 180 days for yc + fund raising

[ig1]

Can you fly out the country and come back again for another 90 days ?

[pclark]

In theory if you can prove you do not live in USA. It's a stress.