Popular video-sharing Web site YouTube Inc. has agreed to post Japanese language warnings about respecting copyrights in an attempt to prevent users from uploading copyrighted materials, a Japanese entertainment body said. The Japan Society for Rights of Authors, Composers and Publishers said on its Web site Tuesday that YouTube notified it of the move in a response dated Dec. 15 to Jasrac's request earlier this month for a series of measures aimed at preventing uploads that infringe copyrights.