Gillette teams up with Tinder

Gillette has giving the dating app Tinder advertising money, but you won't see the razor company's ads on the app. Instead, Gillette has paid Tinder to test the theory that unkempt facial hair is less desirable than a well groomed face, according to Ad Age.

The two companies worked together to analyze 100,000 men on Tinder. Gillette says that the well-groomed men got a more positive response on the app. They received 74 percent of the total right swipes, meaning they're desirable on Tinder. The well-groomed men also received 37 percent more matches than the men who showed photos displaying facial hair.

So Gillette got useful information from Tinder in exchange for advertising dollars, even though Tinder never displayed a Gillette ad. The unlikely partnership is just one of the examples of how free smartphone applications are able to rack up revenue.