There are only two categories:

General
(open source, open standards) We’re looking for people with great ideas
who don’t quite know how to make them happen, or people who have an
exciting idea they want to test. You just have to use digital news and
information in a new way to create a sense of community for people in a
given geographic area.

Commercial
– Your idea is a for-profit product or service that will have positive
social impact. This category is for entrepreneurs whose ideas might not
have enough profit potential for venture capital. If you have an idea
we like in this category, we will help connect your company with the
funding it needs. We want more corporations to think about the double bottom line.

So the only question is whether your idea is for-profit or not.