Before the movie "The Ring" came out in America, there was a large amount of hidden advertisements through random websites. Some of these include lore of the characters, or knowledge about "the tape"
These websites can easily be found on the Wayback Machine's web archive service, but not everything has been snapshot. Including 3 Teaser Videos that were hosted on the sites Sadakoisdead.com and Samaraisdead.com
The first one Sadako1.mov, was an abstract 30-ish second video
The second one, which the name hasn't been recalled, was more abstract than the first. It apparently contained slight spoilers for the movie
The third video however, titled Bloody1.mov is the most recalled and most notable video, it contained a man with a knife, stabbing himself in his mouth, as if he was brushing his teeth with it.