Nielsen Admits to Undercounting Web Traffic

By Andrew Gauthier 

Advertising Age

The Nielsen Co. disclosed today it has been undercounting traffic to websites — for at least the last three months — due to a flaw in its system that failed to recognize long internet addresses, underestimating “time spent” on the internet and especially social-media sites.

Nielsen is still investigating both the cause and extent of the error, but is advising clients in a letter today that it believes their “time spent” metrics — or the amount of time visitors spend on a website or watching video — may be grossly underestimated by the current system. More…