How do url shortners make money?

Everybody use url shortners these days. But my question is, how do url shortners like bit.ly make money?

 

I know off of Twitter - I use tinyurl.com to shorten my URL and then tweet it to my money page.

 

Well... budurl.com makes money on his "members area"

 

Generally they get funds from big companies just like twitter.

 

By Adsense. Ex : Just check tinyurl.com. and see in the right side, you see google ads. So i can say each url shortener sites, have different sources of earning.

 

Most from ads, you mite have noticed an ad on full page with a option skip this ad. And many more

 

You can place ads on your page , eg: Adsense, Adbrite etc

 

just like any other sites. they still have ads n their pages.

 

Ok. But how many of you actually visit the shortening service website? I mean I never do. I always shorten my url by some extention or API.

 

most people use it to mask a referral id for a affiliate program

 

You can make money from shorten URL's if the URL you've shrunk would be used regularly or have many traffics because every time somebody clicked your shortened URL there's an advertisement before they can actually see the main page of your website. For every advertisement shown, You can earn from it.