US taxes for affiliate earners

Pointers needed for my tax guy

[saoi_jp]

If you have a day job, and also earn affiliate income from affiliate programs, how do you classify that on your US taxes?

I live overseas, and my tax guy is an expert in taxes for expatriates living in this country. I don't expect him to know about US-based affiliate program earnings. He thinks I'm a salesperson for Amazon. I've heard some people claim "hobby income" etc. but I need the official terms (and form numbers, if possible) to tell this guy, so he knows what to look up.

Just to stress: I know not to take forum post advice as legal advice. Any pointers will be sent to an expert.

[rcjordan]

I split my company's affiliate sales and lead earnings as "sales commission" and CPC and CPM as advertising income. If it's a mixed check (as from some networks), I'd categorize it by the larger group $$-wise.