The recently launched Startup Warrior from former Georgia Tech classmate Andrew Cantino utilizes the Crunchbase API to help visitors visually browse startups and view startup hubs. Since the launch, Crunchbase has added similar mapping functionality but it's up to you to decide which implementation is more effective.
StartupWarrior.com allows you to learn about startups in your city or neighborhood, both for job hunting and for networking with your peers. This website began as a personal project to identify geographic regions with the highest concentration of startups. The map helps to illuminate both the diversity of startups in hubs like Silicon Valley and London, and the growth of other startup communities in the US and abroad.
The only feedback I have for Startup Warrior is that I would like to sort the startups in other ways than just location. For example, being able to show the 20 most profitable startups or the most recently created startups. It would also be neat to show startups by creation date and see startup hubs form as you move the date from say 2002 to 2008.
What do you think about Startup Warrior and other such startup tracking services?
Update: ATLlogos is a related site that helps people find and learn about Atlanta-based early stage technology companies.