Online counting error cost top sites 5% of audience, says Nielsen

Problems were linked to the presence of long URLs, which when encountered caused the company’s counting technology to fail to recognise and record the online session.

Social media gaming sites were more affected than other categories, Nielsen said in a note to clients. Its VideoCensus service was also “significantly less” affected than the NetView tool.

Nielsen said it had now found a way to make sure it counts websites with long URLs and is currently “final testing” the solution.

It aims to have the fix in place for the release of the December data, and it will be also be applied to the November numbers, which will now be published at the end of next month.