Advertising on porn sites: Don't knock it until you try it

You won't see blue chip companies advertising on a porn website. At least not yet. Those American icons don't need to. They have images to uphold, and they're awash in advertising money to make sure you see their products whenever, wherever.

However, when you're a self-funded start-up, you have to be creative … and perhaps a little less straight-laced.

A food delivery business called Eat24 is boasting that it has gotten a lot of bang for its buck by placing ads on porn sites.

Sound crazy? According to ExtremeTech, "It's probably not unrealistic to say that porn makes up 30 percent of the total data transferred across the internet."

Who's crazy now?

Eat24 management reports in a blog called "How to Advertise on a Porn Website" that, "When it comes to spreading our brand message, we usually take the road less traveled."

Since the company claims it has taken absolutely no money from outside investors, it was trying to find ways to spread its message on a big scale for little money. "The Solution: Porn, the Internet's Unicorn."

Eat24 said some of its biggest fans were pornstars, and several sexy leading ladies were already tweeting about the California-based company before it started advertising. (Really? Porn stars are going to talk about a food delivery business on Twitter merely because they're "fans"?)

Anyway, Eat24 says it started doing some research and discovered that by putting ads on porn sites, it could get more ad impressions than on Google, Twitter, and Facebook combined—for only a tenth of the cost. In other words, the advertiser would get more, er, exposure, on the porn sites, for a fraction of the investment.

(Read more: Porn group lifting HIV-prompted filming moratorium)

The porn audience also seemed tailor-made for the food delivery business—mostly male, probably not dressed to go out. In addition, Eat24 said there was little competition: "Almost all of the existing banners were just more porn. The rest were for male enhancement pills, tips on how to please a woman, and finding hot local singles near you."

So the company dove in, coming up with racy ads like "BLT with your BDSM?" (Bondage & Discipline; Sadism & Masochism for the uninitiated.) The company learned that porn sites would not allow ads that included monkeys, cats, or dogs. And it discovered that by posting an ad on a page with video, the ad got five times as many clicks.

"Even if their focus is on what's happening in the larger screen, subliminally,they're thinking about sandwiches," Eat24's blog claimed. "Plus, after they're done with the video, they've worked up an appetite."

Could this be the beginning of a trend? Might more companies find advertising on porn acceptable? PandoDaily recently reported that another company has chosen to promote itself on an adult site. Subscription underwear business MeUndies began running ads on porn start-up PaintBottle.com.

Subscription underwear! Porn start-up! This is what happens when young people can't get regular jobs anymore! MeUndies founder Jonathan Shokrian told PandoDaily: "We're always looking for new ways to get our brand in front of people. ... If that means a little bit of controversy, so be it."

It's a learning process for everyone. Eat24 says advertising on adult sites has taught it a lot about its consumers, including:

If it really is a billion dollar idea, may some blue chip companies get involved?

—By CNBC's Jane Wells; Follow her on Twitter: @janewells.