Counting Clicks: Now A Mainstay

"Our business is not to put a financial spin on things. . . . There isn't one single number that's going to predict how a company's going to do in the next 10 years," he said.

ComScore gets its massive amounts of data by tracking what more than 2 million people are doing online, similar to the way Nielsen keeps tabs on what TV shows certain households are watching. The company recruits panelists with sweepstakes contests and by providing faster Internet service or free virus scans. Nielsen NetRatings also uses a panel of Web users, recognized as the most accurate measuring method.

Dozens of other services, such as Hitwise, Compete.com, Quantcast and Google Analytics also gather Web-use data and slice and dice the numbers in different ways. Some get traffic information from Internet service providers or from Web sites' internal logs.

On the discrepancies between the data of ComScore and its competitors, Abraham said the debate is inevitable: "When you have two watches, you're always going to be in a quandary about which one shows the actual time."

Ramsey, of eMarketer, said inconsistencies arise because each measurement firm defines audiences and traffic differently and analyzes the data in its own way. One firm may measure how many total hits a particular site receives in a month, while another may measure how many unique visitors come to the site during a slightly different period of time.

Complicating the measurement process is the fact that some people periodically delete the "cookies," pieces of code that track which sites they visit. And automated crawlers can skew the data for some sites.

Abraham said ComScore's technology can recognize legitimate traffic and account for cookie deletions.

Some of his clients say the actual numbers matter less than the trends they can extract from the data.

"If one service says you have 20 million unique visitors a month and another says you have 22 million, you can still look at the bigger picture," said Haroon Mokhtarzada, chief executive of Silver Spring-based Freewebs, which allows users to customize Web pages. "ComScore's become the gold standard for sure . . . we know all the (ad) agencies are looking at their numbers."

Mokhtarzada looks at other services' data to supplement his internal data and the numbers he gets from ComScore. He said ComScore's data reveal demographic details about Freewebs' audience that other services do not.

"We realize the numbers aren't perfect, but they're the best apples-to-apples comparison we have to narrow down the sites to deliver targeted ads," said Meridee Alter, senior vice president of Rubin Postaer and Associates, whose clients include Honda and MGM Studios. The marketing firm also subscribes to some Nielsen NetRatings products but relies on ComScore for online traffic data.

The economic downturn is already taking a toll on some of ComScore's biggest customers, which include Microsoft, Pfizer, Citibank and Ford. But Todd Greenwald, senior analyst at Signal Hill Research in Baltimore, said ComScore has become so integral to an online firm's business that it will probably weather the storm.

"For online retailers, having ComScore's data is almost like having electricity or an Internet connection," said Greenwald, who closely watches ComScore stock. "It's a cost of doing business."

Abraham said ComScore's customer base is diverse enough to protect the company's business from softness in one sector of the economy. ComScore is also focusing more attention on the growing mobile industry and it acquired Seattle-based mobile research firm M:Metrics in May.

About 80 percent of ComScore's revenue comes from multiyear subscriptions, and the company typically signs up around 50 new subscribers every quarter. But that growth could slow if potential clients are less willing to add expenses, said Mark May, an analyst with Needham & Co.

"I think renewal rates will continue to be high," he said. "The product they offer is a must-have for their customers."

The next milestone for ComScore will probably come when it completes a rigorous audit by the Media Rating Council, an industry group that reviews major audience counters for a variety of media.

"This is something that all the traditional audience firms have been doing for decades," May said. "That will bring some validity to their methodologies."