An April Fools' Day joke perpetrated by the c't magazine. c't claimed that IP routers actually implemented QoS, but nobody had ever thought of using it, so they wrote an FTP proxy which (so they claimed) would give your requests the highest priority so that you'd get the full download rate even during the Net's rush hour.

This program actually worked, but it never downloaded anything; instead it created dummy files. If the downloaded file was an executable (which was true in most cases, as it was a Windows program), it'd pop up a dialog box saying "April Fool!" when executed.

The article in the magazine in which the program was introduced claimed that the QoS fields in the IP headers that it supposedly relied in were defined in RFC 1414. In Germany, dates are written day first, then month...