2 things come to mind.

1) Customer Service at Scale - If I am a business owner people call up with questions that can most likely be answered by an faq and a search. Worst case they are checking on the status of an order or something that might require a dashboard/database lookup, but could easily be provided to a 3rd party. I would imagine providing a scalable way to outsource this process to business might be something to tackle. Checkout http://bootstrapped.fm/bootstrapped-episode-18-special-guest... might get some ideas - just think millions of customers and only 10 reps

2) Call Me Back - Rather then wait 25 minutes on hold for calling some company - have a service that calls in and press 0 and waits until someone live is on the phone then tell them to wait while I connect me and call me back

3) Mass Notify - When an emergency happens - why not have a simple solution for calling out or sending sms. When businesses are closed or sports games are cancelled, a simple way to send out a notification

Just some thoughts -

Big Players: http://www.ringrevenue.com/ https://www.twilio.com/