What if you created an all-new and substantive app/service category?

It's often said that there is 'nothing new under the sun' in terms of online apps/services. The hundreds of Twitter clones running around calling themselves disruptive underscore such a viewpoint, but let's set that aside for a moment and for fun assume the following is 100% true/certain:

1. a startup has created a web app/service which is so original that it creates a new category without any direct peers/competitors.

2. The startup is at a prelaunch stage, but the development version of the product works.

What, if any, special advice would you give to such a startup?