My suggestion (which is worth exactly what you paid for it) is this: find someone who has no contact with the IT world beyond, maybe, a passing familiarity with mobile phone apps and Google Mail. Tell them you want a one-sentence description of your own business. Give them as much information as they think they need, explaining everything in sufficient detail so they feel they understand it. Then ask them for their one sentence. Write it down. Do this a bunch of times. Finally, take all the collected sentences to someone who does understand IT but knows nothing of your business, and get them to condense them all into a final description.
I strongly suspect the result will be an improvement!
That's a great suggestion. It will certainly be an improvement. Just explaining it to a wide variety of people can help your thinking about it. If you get outsiders to describe it for you, even better.
Maybe I should've stayed at Google then? :)