The Internet was supposed to be the marketing professional’s dream – a marketplace where every consumer leaves a permanent record of what they looked at and what they eventually bought. On the back of such promise, online advertising has flourished, with global spending falling just short of $17 billion in 2006.

But all is not well in this commercial paradise. In April 2007, Randal Rothenberg, president of the Interactive Advertising Bureau, wrote a stern letter to comScore and Nielsen NetRatings, the two giants of online market research, berating their research methods.

“Imagine my surprise,” he wrote, “when I discovered that the main audience-measurement companies are still relying on panels,  a media-measurement technique invented for radio seven decades ago.”

In the same week, both companies issued their own statements criticising web measurement techniques employed by most businesses. ComScore rubbished ‘unique visitor’ counts, while Nielsen claimed that page views are no longer relevant.

It appears that tracking online behaviour is not as simple as it was once thought. And this endangers a booming market. As Rothenburg put it to comScore and Nielsen: “The one issue the Internet was built to resolve, audience measurement, remains a burning platform.”