Revolutionary meaning a competitive technology edge that is very hard to copy. However, I believe it has first to solve a business problem that hurts people - who will want to use your product/service as they will find value in it, so much value that they are willing to pay and become your customers. All the best with your YC application.
I've always been a social technology person; anything that allows people to communicate better or find information faster; hopefully the startup i'm creating is able to create such value for users and thanks!! though I think chances for entering YC is slim but its worth a shot :)
