You really think this will work do you. See, the majority of businesses/sites that visit a website just to read adverts is small, even less will make a purchase and less will consider linking.
I'm betting my business on it.
I expect you're reading the part where I said people 'need' it as a faint hope on my part. It's more along the lines of a professional obligation to have this product available, not a nice-to-have.
Say you're a home inspector and you develop a gadget that does something important, like I dunno, tests for mould. Other mould tests cost $2000 (I'm making this up, I have no idea), so people don't do it. Your new gadget retails at $300 - but you offer it to other home inspectors for $100 and a link to you website.
You now have two classes of home inspectors. Class A gives you links. Class B saves the $100 and lives nervously over inspecting a house that has mould that they didn't detect. A lawsuit waiting to happen.
For those that are looking at this trying to replicate this, this wasn't just a bright idea (though that was the seed of it, it was a question/problem I've seen in the industry for decades, just not a 'big' problem). I also spent months discussing it with vendors, developing it, dealing with lawyers, etc. It might look externally like a simple idea, but it's been months in the making. Might actually take it live today with any luck, then it's time to start link begging.