I run an international social network app. We have users in over 140 countries including the USA. In fact, I registered it as a USA company 3 years ago. Next Spring, I'm moving to study in the USA on an F1 visa. Is this legal? Also, if I'm finding investors or getting more clients or media interviews will this be a problem for my investors or my school?
Ugh... If you register as a US company + you're actually in the US, you may be liable for US taxes.
Personally, if I lived outside the US, I'd organize/domicile my business jurisdiction elsewhere.
If you keep your US company registration, then first item on your list when you arrive in the US is to work with a tax professional, to determine your tax liability.
Then, if you have any, you'll require paying US quarterly taxes.
In fact, depending on where your banking is now... country where account lives where money settles, you may be liable for US taxes.
Likely best to get all this straightened out before you enter the country.
Mucking about with having a US company when you're not a US citizen may cost your a truckload of money.
Talk with a US tax preparer.
A good place to start is H&R Block Executive services, which is very different then H&R Block Consumer services.
Many countries have an H&R Block Executive services branch.