Mine came about back when I first started on the 'Net back in the late 80's early 90's on some of the early freenet services. Mostly just text email and bulletin board type stuff. Anyhow, someone was talking to me about something once and accused me of always having my head in the clouds. So I started ending my messages with "signing off from the ozone layer", which became "signing off from the ozone", which became just Ozone. Common enough word that it's frequently taken, so I tacked the year I was born, 69, on the end.