I remember that! From around 2001-2003, a good chunk of the Top 40 tunes found on file sharing networks would be one verse, looped over and over so the MP3 duration was equal to that of the actual song.

This worked best on mainstream P2P clients like Limewire, Kazaa, Ares (all based on Gnutella I think), because the fake MP3s would propagate more widely.

It didn't work as well (or at all), on relatively obscure, community-based networks like Slsk, where people were more likely to share entire albums, and not just the singles.