Metro NY is roughly 4 times larger than metro ATL and only has 2 times the number of tech jobs... Of course, this comparison is pretty much as valid as the craiglist one.
This is always an interesting question for me. What exactly is a "startup" I recently created a technical services company (software design and development). I don't consider it a "startup" per se, mostly because I'm not creating a product so much as a service.
Anyway this report is about new business creation which is an interesting data point.
http://atlanta.craigslist.org/eng/