Wikipedia is a great reference tool on the Internet. However there is one copyright issue that has recently come up. It has to with listing Television DMA markets on Wikipedia web site. Nielsen will no longer allow Wikipedia to do this because of Digital Millennium Copyright Act.

The statement from Wikipedia.. Due to copyright issues referenced by Nielsen Media, we cannot list the media markets as exactly listed by Nielsen, nor give their rankings. Instead, a list of markets according to Metropolitan Statistical Area, as well as territories and areas unranked by Nielsen, will be listed below. Items that are redlinked will be available soon.

It should be noted that Arbitron market rankings for radio. Is still listed on Wikipedia for now.

I am surprised that such a seemingly trivial piece of information would be the subject of a copyright controversy. If Wikipedia had detailed breakdowns of the ratings, then I think that Nielsen would be correct to complain.

Wikipedia has now removed Arbitron market rankings for radio.