Travelwritten

ABOVE: A Web page for prospective clients of Nielsen NetRatings. 

by Durant Imboden, Europe for Visitors

ComScore Media Metrix, Nielsen NetRatings, and Experian Hitwise are online equivalents of traditional media-rating services like Nielsen (TV), the Audit Bureau of Circulations (print publications), and Arbitron (radio).

Large advertising agencies, corporations, and media buyers subscribe to the services, which provide traffic statistics and other data that advertisers use to plan their ad campaigns.

Unless you're in the advertising business or have extra money lying around for a subscription, you won't have access to the ratings service's information about your site. Neither will your competitors or PR people, unless the latter use CisionPoint software, which licenses data from Comscore Media Metrix.

One of the rating services' quirks is the fact that, for at least some of them, a Web publisher can assign his or her site's traffic to another entity. 

For example, we're represented by the Travel Ad Network, and--like many of the network's other publishers--we assign our traffic to TAN, which is then able to sell a large "aggregated audience" to advertisers. 

There's nothing sneaky about this practice, which is convenient for media buyers who often purchase millions of display-ad impressions at a time. However, it may be confusing to people outside the advertising business.

Next article: Simple exposure vs. decision support