Brainstorm ideas, not fully baked: Ads. Yeah, they will be closing the browser as soon as their phone rings, but you will still have them for a bit before then

Brainstorm ideas, not fully baked: Ads. Yeah, they will be closing the browser as soon as their phone rings, but you will still have them for a bit before then. Make them watch an ad before they can input their number and make the call. Charge them to call the phone. Maybe the first time is free, $0.25 thereafter. Or possibily make it so you can call the phone once by manually typing in the number, but if you want to do it again, it requires the number again and a captcha. But for a fee the system will call the phone, wait 1 minute and redial the number automatically--maybe 10 times or until the phone is answered. (I suggest this because I know I have hit "send" on my computer to send my missing phone a text message then sprinted into the living room to hear if it beeps there, send another and sprint into the kitchen and listen, etc...) Become an affiliate for similar services which charge a monthly fee. Ads for new phones, contact backup services, etc. (Make the ads easy to find again once they have realized they cannot find their phone and come back to your site.) Make them agree that you can sell their number to telemarketers. Or to a cell phone company who will cold call them about needing a new phone. Charge $0.50 to opt out.