Let's see if I can add some meat to this thread.
Where did the term "Disc Jockey" originate? RADIO!
It's fine and dandy if you have taught yourself how to "mix" music in the garage, in the bedroom, etc.
It's also fine if you don't "mix" music and just push play.
The term "DJ/Disc Jockey" refers to one that plays recorded music.
This taken from Dictionary.com:
Dictionary.com Unabridged (v 1.1) - Cite This Source
disc jockey – noun
1. a person who conducts a radio broadcast consisting of recorded music, informal talk, commercial announcements, etc.
2. a person who selects, plays, and announces records at a discotheque.
American Heritage Dictionary - Cite This Source
disc jockey also disk jockey
n. An announcer who presents and comments on popular recorded music, especially on the radio; a DJ.
The American Heritage® Dictionary of the English Language, Fourth Edition
Copyright © 2006 by Houghton Mifflin Company.
WordNet - Cite This Source disc jockey
noun
a person who announces and plays popular recorded music
[syn: disk jockey]
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I am a (radio) Disc Jockey - and damn proud of it. I cut my teeth on small market radio, started my radio broadcast career in 1979 while still in college and have strong ties to the radio stations in this market today.
I am a (mobile) Disc Jockey - and damn proud of it. I have been providing music playback on a mobile basis since I was a junior in high school.
I am a (club/discotheque) Disc Jockey - and damn proud of it. (my avatar shows me in the booth at the club)
I am a "DJ/Disc Jockey" - period. And damn proud of it.