Advertising Age Article Abstract
More Nielsen Problems: Under-Counting 'Unique Visitors' by 5%
Company Making Progress in Fixing Initial Glitches, but Finding More
NEW YORK (AdAge.com) -- Nielsen disclosed on Wednesday that its online measurement system has been under-counting unique visitors to the top 1,000 sites on the web by an average of 5%, the latest in a series of problems for the company. ...