Who's Counting Clicks, and How

There are lots of ways to measure Web traffic. Here's a glance at some of the more common approaches

by Catherine Holahan

A host of companies are doing their level best to keep tabs on how many people are visiting a given Web site, and what those users do while they are there. Some use tags installed on a user's Web browser, while others extrapolate surfing habits from a sample audience. A handful use a combination of several methods. Here's a glance at a range of approaches, with a look at what each has to say about one popular online video site, Metacafe.

Alexa Internet, owned by Amazon (AMZN)

What: Provides Web-site traffic rankings based on page views and users, and data on site "reach," the percentage of total Internet users who visit the site

How: Monitors sites visited by Web surfers who have downloaded its toolbar, which provides safety data and other information for Web sites

Strengths: Includes country-specific numbers and data on trends; information is free and publicly available

Weaknesses: Panel may be weighted in favor of those who visit affiliated sites such as Amazon; tends to favor sites popular in countries where its toolbar has taken off, such as China; excludes users who surf using Opera or AOL/Netscape (TWX); count can be skewed by technologies such as Ajax that let parts of a page change without reloading

What It Says About Metacafe: Three-month average traffic rank is 148; average reach is 0.37%; site fell 15 notches in rankings over three months, and reach declined 5%.

Compete Inc.

What: Monitors surfing behavior of a panel of 2 million consumers

How: Culls panel from people who have downloaded its toolbar in exchange for information on site safety, traffic, and financial deals; randomly surveys panelists on Internet use; buys data from Internet service providers; devising an approach that uses tracking tags, which sit on a site and monitor visits from IP addresses

Strengths: Large panel; supplements toolbar data with survey data, making it less vulnerable to bias; statistically balances panel to better reflect U.S. population; snapshots free and open to the public

Weaknesses: Traffic reported for smaller sites may differ from those sites' own measurements if Compete's panel fails to include enough of the site's audience

What It Says About Metacafe: 2.5 million unique visitors in March, up 35.6% from the prior month; rank is 602, up 263 notches

comScore

What: Tracks the behavior of more than 2 million people

How: Panel made up of people who have downloaded its monitoring software in exchange for security software and the chance to win prizes

Strengths: Lage panel; statistically balances panel to reflect U.S. population; can provide detailed demographic analysis on user behavior

Weaknesses: Traffic reported on smaller sites may suffer if the panel does not reflect enough of that site's members

What It Says About Metacafe: 5.6 million unique visitors March, 2007, up 40% over the previous month. Site rank by unique visitors: 171.