[dirkdk]

working on your US company, or your foreign company, is not allowed when you visit the US on a visa waiver. You are allowed to represent your foreign company, look for partners/customers, do marketing, visit conferences etc. But not be "productive"

[alexro]

If I write open-source code while on the tourist trip to the US does it count as 'working'? I understand you're not giving advice, just curious

[tricolon]

Doing anything for which one would normally expect to be remunerated counts as work. If you volunteer for a project for which no one is paid and will not be paid (and no one ever expects to be paid), that's not work. But "working for free" is work and so is volunteering if others in a similar role are paid.

At least that's how it's been explained to me.