 servers with large numbers of messages and protecting these servers from spam and viruses. Sonian wrote the software for its archiving services on Amazon's servers by using an Amazon-provided API link. According to chief technology officer and founder Greg Arnette, its business customers' e-mail messages are encrypted before being sent securely across the Internet to the provisioned storage repository at Amazon. Sonian's customers, who typically have 500 to 5,000 employees, are provided with a web inter- face to access information about their e-mail. In this way, IT managers have access to reports on their company's e-mail traffic, and individual staff members can search for their own messages. Using Amazon's services, Sonian was able to build its business without estab- lishing redundant data centers across the country. Arnette feels that this kept his own company's costs low and in turn lets him pass the savings on to his customers. Both Sonian and its customers pay for only what they need, and they can take advantage of Amazon's economies of scale. Sonian pays Amazon for the CPUs by the hour, storage by the gigabyte, and bandwidth by the gigabyte. According to Arnette, its Sonian's client e-mail messages are stored on eight of Amazon's data centers throughout the United States. All e-mail messages are archived redundantly in each of these eight data centers. Akamai's IaaS offering is for content storage. It hosts large enterprise web sites as well as 50 of the top e-commerce sites. Thus, Akamai provides IaaS as well as PaaS. Computing as a Utility Cloud computing companies often refer to computing as a utility. In his article "Planet Amazon" (Wired Magazine, May 2008, page 92), contributing editor Spencer Reiss quoted Amazon's CEO Jeff Bezos regarding his stance on cloud computing. "You don't generate your own electricity," Bezos says. 'Why generate your own comput- ing?" The phrase "computing as a utility" implies that computing services are not highly differentiated from one another. They are necessary to r