look up any word, like fellated:
 
1.
In the mid 1990s, "Altie" was used to refer to someone who subscribed to an alternative lifestyle-- whether skateboarding, proto-goth & emo, or punk.

"I could never date Chris, I'm a cheerleader and he's an altie."
by makr6000 October 03, 2008
 
2.
Used in Usenet groups belonging to the "alt.*" hierarchy. Specifically, members refer to themselves as "alties" when posting about a fellow member of a newsgroup.

In the example below, the term "altie" indicates that "Mike" is a regular contributor on the alt.coffee group.
"Mike, a fellow altie, sent me some great tips for using my new Bunn drip brewer."
by Kevin Wimberly May 05, 2006