When 47-year-old Paul Oyer started online dating after 20 years off the market, he realized his work as an economics professor at Stanford University might be helpful.

The theories he'd been teaching in the classroom applied directly to his forays into Match.com and JDate. Thick markets are more powerful than thin ones - use a big dating site. Rational people sometimes choose to lie - don't list all the viral videos you like. Skills matter - being good looking helps. His knowledge of IPOs could teach him about where to take his date for dinner (answer: somewhere expensive).

"After my first date, the thing that triggered in my mind is that this is all about markets," he said. "And in the intervening 20 years between when I first dated and now, I'd learned a lot about markets."

His book, "Everything I Ever Needed to Know about Economics I Learned From Online Dating" (Harvard Business Review Press; January 2014), breaks down online dating into basic economic principles. Online dating software has been built by statisticians, engineers, and nerds - and maybe nerds are the ones who need to start breaking it down.

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Q: IPOs can teach people how to date?

A: Definitely. Some people say Twitter blew their IPO by underpricing the stock. But it's possible that they purposefully wanted to signal to the market - we're going to treat our investors well, and we're willing to signal that by leaving some money on the table. The next time they go to the market, the investors are going to think of that. Signaling has to come at some expense to yourself.

It's the same as burning a huge pile of cash on a first date. It signals, "Hey, I'm going to treat my investors well."

Q: How did Facebook teach you about which site to use?

A: Facebook is a product with what we call network externality - demand is driven by demand. Why do people go to Facebook? Because people go to Facebook. Online dating sites have this same attribute. Why do people go to Tinder? Because other people go to Tinder. Demand is driven not by the product but by other users.

Q: When do you stop searching and just pick someone?

A: The word settling is so unromantic, but you cannot possibly choose from all the possible mates online. Back in the day you had to put on nice clothes and go to the bar - or call your friends and say, 'Hey, don't you know someone?' Now you can keep scanning through profiles. There are millions of options. Just as everybody accepts a job that doesn't have that last little perk they wanted, at some point you have to accept a life partner.

The partner market is one where both sides have to settle for each other - just as in the job market. It's different from grocery shopping - you go grocery shopping and the groceries don't have to love you back.

Q: What should online dating sites learn from economics?

A: One thing is verification of information. There's a lot of lying on dating sites and there are simple ways to verify it - there are Chinese dating sites that ask you to send in your tax returns and a photocopy of your license so people can't lie about their age or income.

And there should be ways to more directly signal. You want to allow a mechanism that says, 'I'm interested in you and I mean it.' I can write anyone a little message that says, "Hey, I think you're hot." Why don't we ask people to put their money where their mouth is?

Q: Mailing someone your tax returns?

A: Donating to a charity. And this is my little theory, but you could say, "With this message, I'm showing that I want to meet you and am donating X dollars to some cause to prove it." That would show that I'm willing to spend money. And the charity I choose might signal something very strong. I might send my money to a soup kitchen and another guy might send his to the NRA.

Q: Do your students read the book?

A: I teach MBA students typically, but I haven't asked them to read it because it might be weird to discuss my dating life. They're all probably on to some cooler dating site, anyway. But I do like the idea of explaining economics in a context where no money is transferring.

Q: You ended up meeting another Stanford professor who works 100 yards away - and you've now been together a year and a half. You couldn't have just walked over there?

A: She may work 100 yards away, but we didn't know each other!

I think it's a further reminder that you want to go where the market is - and the market is online. For middle-aged people out looking for their next partner, the thick market is online now.

Q: Are there any points where online dating as economics class might not work?

A: Have you ever heard of OnLulu.com? You review boyfriends. It makes it more like an eBay-type thing. And that has certain advantages. But there's a certain emotional side of reviewing ex-boyfriends that you're not going to suffer from (if you're) reviewing something on eBay.