[foulmouthboy]

Sponsorship. Localized.

You know the person's area code. Make the assumption that they live somewhere near there and sell local ads.

I wouldn't put the advertising in the voice message itself. Most users are just as likely to ignore the call once they get the phone. After the number has been submitted though, the ad can display on the website's thank you page.

"Now that we've helped you, return a kind act and consider one of these fine products from one of our sponsors."

[paulnelligan]

Or just have the ad on the page as soon as they input the area code using some ajax magic ...

would work great for pizza ... stoners lose phones a lot, they also love pizza ...

[andre]

everybody is going go close out the site ASAP after the phone rings, so any ads you post will be very ineffective.

Since you know they'll be calling their cell phone, consider sending them a text message after they make the call: "Now that you have found your phone, consider ABC company in your city for xyz."

Add this to terms of use.