Microsoft announced that it is selling advertising space in the error messages that appear in Windows. Acknowledging for the first time that the average user of their operating system encounters error messages at least several times a day, Microsoft is trying to take financial advantage of the unavoidable opportunity to make an ad impression. "We estimate that throughout the world at any given moment several million people are getting a "general protection fault" or "illegal operation" warning. We will be able to generate significant revenue by including a short advertising message along with it," said Microsoft marketing director Nathan Mirror. The Justice Department immediately indicated that they intend to investigate whether Microsoft is gaining an unfair advantage in reaching the public with this advertising by virtue of its semi-monopolistic control over error messages.