Effectively if you're promoting a product in exchange for compensation, that relationship must be disclosed at the genesis of the click and according to the FTC no compensation is too small to be in violation w/out disclosure.
BUT that being said, I think there is a big opportunity here - to make the disclosure automatic AND possibly even user friendly. Right now disclosures are really ugly and create friction in the user experience, maybe we can fix this.
And if the refer.ly brand becomes widely known and recognized, that would help too. Definitely something we want to help sharers do in the most streamlined way possible
EG "[Firstname] thought you'd love [product name] from [vendor]. For spreading the love [firstname] gets a referral fee if you buy! Find out how you can start making money referring friends to products that you love too with Refer.ly today!"
The reason is that information doesn't generate itself. If you Google BlackHole5000 coffee extruder review, the BlackHole5000 coffee extruder being this great industrial high-pressure coffee maker, and you don't find a single review, that means in a way there is this 'commons' that is empty now. If there is no Wikipedia article on it (maybe there shouldn't be) there is also an empty 'commons' there. Now compare this with a Wikipedia article being there and being informative: (say the BlackHole5000 is extremely notable, as destiny would have in 20 years) if someone were to completely blank that page out or vandalize it beyond usability, then until this issue is rectified it's pretty clear that they have taken someone from a 'common good.'
Now my argument is that if people take the time to post their review of the BlackHole5000, for me to find, that is also kind of a public good. (After all, they're free to browse if you can find them, etc.) If Google and every search engine were to be completely buried in SEO spam, such that the legitimate reviews are impossible to find, no matter what, by anyone, then it's pretty clear the public loses something. It's like air that you can't breath anymore because it has too much pollution in it. A lake can literally be too toxic for anyone to camp by it, even if it doesn't belong to anyone.
Now what may irk some people here even more. What if we don't completely bury the legitimate reviews, but only adulterate them with paid shills? Before I get to this, let's take a simpler example of attacking a public scientist or activist's message by 'poisoning the well' (attacking their credibility in a false and underhanded way, just to keep the audience from appreciating the message.) In my world-view, there are whole fields and areas of human endeavor which have NO credible scientists and are ALL opinion. To me, the freely available opinions of credible researchers who have invested months or years into understanding to tell me about it is also a kind of 'public good.' There is no reason anyone has to lie to me about how photosynthesis works, and YET it is part of the public good that I can do a google search and immediately get to credible opinion on it. Luckily, photosynthesis is one of the few areas of humanity where there is simple, credible agreement.
If someone were to add a bunch of 'poisoning the well' type junk, then photosynthesis would be like the effects of smoking on the human body, would be like the causes of automobile accidents, would be like labor conditions in China, would like a million different subjects that just have opinions on them but no real credible consensus for anyone who searches. We should cherish credibility and it should be a crime to knowingly "poison the well" in my humble opinion.
Now we return to what I was saying about paid product reviews. In this case, genuine customer satisfaction is also a kind of "public good" -- if you dilute it, it disappears, and if you dilute it enough no one reasonable would ever search for "BlackHole5000 review", since the result is as good as guessing: no relationship with customer experience.
But if it becomes ILLEGAL to dilute it in this way, and these laws work, then something magical can happen. Suddenly, if people know that googling for reviews 'works', then if the BlackHole5000 is off the charts, then anyone who is curious enough to try the Google search will see this, try the BlackHole5000 and within a few years it is a cult icon that truly deserves a Wikipedia article. Which never would have happened if customers knew that searching for reviews online was useless.
Basically, if we want to live in a world where better products win, then I think we should cherish the 'public good' that is customer opinion on that product. The most obvious objection about free speech already doesn't apply to being able to say whatever you want to sell your product (e.g. 'the BlackHole5000 cures cancer our studies find', without any mention of the FDA) so why should you be able to pay others to talk about your product as though they weren't paid?
Basically, it's hard enough to get people to put up a genuine review that is useful, period. (It takes work and thought). We should cherish the few results, when they happen.