I have a friend who regularly calls me from his cell phone with random questions that he hopes I can answer. The conversation usually goes like this:
Friend: "Hey, are you near a computer?"
Me: "Yes." (I usually am.)
Then he proceeds to ask me a question that I type into Yahoo! Answers and I read the answer back to him. Anything for a friend, right? But so inefficient!
Now my friend won't need to use his phone to call me to ask his questions -- now he can go straight to the source using Yahoo! Answers on Mobile built on the Yahoo! Answers API. Read Kevin's blog for the details on why he built the application (Kevin is a "soccer dad" in Colorado).
The Answers team here at Yahoo! loves it and Jeremy does a nice job of putting Kevin's work into the bigger picture of what open APIs mean.
As Eric Raymond famously wrote, "Every good work of software starts by scratching a developer's personal itch." Kevin's particular itch was understanding soccer since his daughter had just started playing, but yours is probably different. Take your pick among our many services and surprise us with your creation -- the possibilities are indeed infinite.
Yahoo! Developer Network