The IAI, developed in conjunction with market research firm Nielsen//NetRatings, divides Internet usage into four distinct categories: content, communications, commerce, and search. The service will track the share of consumer time spent doing each activity, and will be updated on a monthly basis.
According to the IAI's June 2004 figures, communications saw a 2.3 percent lift over May, accounting for 43 percent of all time spent online, followed by content, which posted a 37 percent share. Commerce took a 17 percent share, and search, a 5.3 percent share.
The IAI also measures the total number of pages viewed per month in each category (in billions), the average number of pages viewed per person, the total time spent using each category (in millions of hours), the total number of unique visitors per category (in millions), and the percent reach of each category of the total online population.
According to Pam Horan, The OPA's vice president of marketing and membership, the index will provide "a benchmark" for charting the impact of changing market dynamics on these categories. She added that it will be a way to track the manner in which the Internet evolves.
For example, Horan noted a spike in the number of unique visitors to e-commerce sites following the 2003 fourth quarter holiday season. "Coming off [the fourth quarter] there, a halo effect was put into play that sustained itself through the spring," Horan said. She noted that the IAI will also be useful for tracking month-to-month and seasonal trends.
For marketers, Horan said, "as they build their marketing plans and determine how they will get their message out, it will be important to note [consumers'] relative involvement in each of these areas." The IAI will remain a sub-section of the OPA site; Horan added that as significant shifts in consumer behavior occur, the OPA will be sending out media alerts and press announcements.
Nielsen//NetRatings NetView service provides the click-stream database that generates the index. The company said that it calculates the usage metrics using the same algorithms it uses for all NetView-based custom analytics offerings.