• by Wendy Davis  @wendyndavis, March 8, 2006

Research company Nielsen//NetRatings' AdRelevance unit erred in recent monthly reports stating that the number of ad impressions on MySpace fell in November and December.

Earlier, Nielsen//NetRatings had reported that the social networking site's share of display ads plummeted to 7.9 percent in November and 4.8 percent in December. Nielsen//NetRatings now says that it undercounted the ads on MySpace those two months.

During that time, "we experienced technology conflicts with our ad detection software and the level of disparity was focused on MySpace's reporting," a Nielsen//NetRatings spokeswoman said in an e-mail to OnlineMediaDaily.

OnlineMediaDaily reported the incorrect data in stories about online display ads in December and November, as well as a story about an upcomingPlayboy "Women of MySpace" feature. The company is not able to now calculate how many ad impressions MySpace actually served in November and December. "If data was missed due to technological reasons like what we experienced on MySpace, there is no way we can recreate the environment found during a specific past time range," stated the spokeswoman.

She added that the company is standing by its October and January calculations, showing that MySpace garnered 10 and 10.1 percent of all ad impressions.