Fad? I don't think so.
The interest in this exciting hobby is greater than most of us might think. New songs are released every week. There are karaoke places everywhere.
A search on Google shows 2,730,000 instances.
As for the history, George expressed it very well. Here is a link for more about "
Karaoke History.
http://www.itksuperstore.com/page30.html
Jon