Doubts Arise About Web Traffic Tracking

If you think the internet makes tracking audience numbers any easier, think again. Media companies sometimes report millions more online visitors to their sites than tracking companies like Nielsen—because they use different measurements—and the gap makes online advertisers queasy. It's preventing the industry from growing as quickly as it could, the Times reports.

The internet may allow recording of a specific number of visits to a site, but tracking individual visitors is a lot trickier. Just one example: Media groups accuse ratings companies of underestimating visitors who use the Web from work. One researcher says of the internet: "People keep talking about it as much more accountable than other media, but we're not finding that to be the case yet." (More internet stories.)