IP addresses are going fast and are in danger of being all used up in 2010, according to researchers at the University of Southern California's Information Sciences Institute. That suggests online retailers who are taking a niche approach to the market and want to create subbrands should get their niche sites up soon.

The researchers just completed a census of the Internet and report the existence of 2.8 billion IP addresses, the 10-digit addresses separated by decimal points (69.67.214.151), out of a possible universe of 4.3 billion. Although niche retailers create separate URLs for each market, not every URL is a separate IP address. IP addresses identify servers and so URLs that reside on one server share an IP address.

"As Internet use becomes widespread, we are running out of Internet addresses," said John Heidemann, project leader of the Information Sciences Institute and associate professor in USC's Computer Sciences Department. "The Internet Engineering Task Force, the technical body that manages the Internet, has anticipated this since the 1990s. It has designed a new protocol, IPv6, to solve this problem, but deployment has been slow. Our data helps illustrate the need to move forward."

In addition to documenting the expected depletion of IP addresses, the census is helpful from a security point of view, the institute reports. Other Information Sciences Institute researchers are using the census data to study how worms spread in the Internet and to plot maps of where cyber attacks originate. Researchers compiled the census by using three machines to send three billion inquiries to IP addresses over two months. USC says the last Internet census took place in 1982, when 315 Internet addresses had been allocated.