Do you have a guess for what "business activity" means and where you draw the line? And yes, YANAL.
Great link by the way, thanks. This guy has to jump through so many hoops just to stay in here, and seems like he was always a couple of weeks away from being kicked out.
You are not allowed to do any sort of work for your company including programming, business development, marketing etc. You can only be an inactive partner in the company.
But practically speaking, you could get away with it while two of you develop the software from your apartment. USCIS is not going to monitor what you have been doing on your computer at home.
It would be difficult when your business grows and have employees & customers. Make sure that you are able to transfer H1-B to your company by then.
I guess founders of few YC and TechStars companies come to US on Visa Waiver Program or Visitor visa for few months and work on their startup.
You can get H1-B visa sponsored by your own company. Manu Kumar of K9 Ventures was able to do this, read http://k9ventures.com/blog/2009/09/24/my-story-and-support-f...
It should be easier for you with a US citizen co-founder.