Strong Startup Categories for Atlanta

After looking at the Atlanta Logos (atllogos.com) site, which lists hundreds of Atlanta startups in different stages, I realized we can do a better job of highlighting the categories, or markets, that Atlanta has a strong base. Historically, people tend to think of Atlanta as a strong market for B2B companies, Internet security (ISS), and logistics (UPS, Delta). Here are some other categories with a strong local base of companies:

• Online marketing software
• Lead generation sites (e.g. RentWiki, Clickscape, etc)
• Vertical ecommerce sites (e.g. Case-Mate, Sylvane, etc)
• Phone technologies (e.g. Cbeyond, Vocalocity, Aretta, etc)

Oh, and Atlanta has the largest number of data centers of any metro area in the country. I encourage people to talk about these other categories, in addition to the usual suspects.

What are some other startup categories with a strong base of companies in Atlanta?