problem solving of affiliate commissions

(1) He's got some websites and he's signed up with something like CJ.com or something similar so that visitors to his website can "click" on on the ads and then earn him some commissions.

(2) The company offering the ads sent him a simple W-9 form that's totally standard in this situation.

OP doesn't need a "business" license ANYWHERE in the United States to do this -- or anything remotely similar. If the OP signs up with the company that's going to be paying him his commissions UNDER HIS OWN NAME, he's considered an "individual sole proprietor" under the law.

If the OP had a website, say "turtles.com" and he signed up for his affiliate account as "turtles.com" then that means he's doing business as "turtles.com." That means he would then NEED a "doing business as" certificate (d.b.a certificate). Even then, he's still considered, under the law of ALL 50 states, a "sole proprietor".

In either situation -- him doing business under his legal name, or doing business under another name ("turtles.com") he's entitled to take legitimate tax deductions on both the federal (and state level if he's got a state income tax where he lives) level.

ALL of his income is taxed together. There's no "personal" and "business" income that needs to remain separate here. The IRS taxes it all at the individual rate. In other words, the IRS is not going to challenge his "business" at all. That's a totally different ball park. That occurs when an individual actually incorporates ("INC") or forms a one person limited liability company (LLC) and then FAILS to maintain the legal requirements for such. Example: mixing personal and business assets. That's called "piercing the corporate veil".

It's one of the many things that IRS would look for under that situation should they audit you and question deductions. They're going to want to know that you've actually operated as a business and not as an individual.

In the OP's case, this is becoming way more complicated than it has to be.

The OP can collect millions in affiliate commissions and never have to worry about a "business license" or "d.b.a." certificate and so on. But the OP is still entitled to deduct home office space/expenses if he operates from home, can take deductions for materials he purchases for his venture, heck, he can even deduct cell phone bills if he's using that solely for the purpose of his little home business. It doesn't matter to the IRS: he's taxed at the individual rate. Period.

So to the OP:

Don't do a thing. IF you end up making $600 or more in affiliate commissions, you're going to get a 1099 from the company (IRS gets a copy, too). Whatever is on that 1099 you need to report on your federal income taxes. That's what the IRS would KNOW about. If it were less than $600, the IRS probably wouldn't find out...

...BUT you're still responsible -- on the "honor system" -- to report it!

As always, if this stuff is really bothering you, consult with a LICENSED tax attorney or LICENSED CPA. Don't leave anything to chance if you've got worries because at the end of the day, you're the one who's going to be facing the fire, not the people here (including myself) that's taken the time to give you some tips/advice/pointers.