This is an old thread, but nobody actually answered your question... so here ya go.
After the resort went corporate, the marketing specialist for the company that owns Purgatory decided to re-name the resort "Durango Mountain Resort" because most people did not know where Purgatory Mountain was and they wanted the name to be associated with the town, they thought it would increase visits/sales...
It didn't work and now only tourists call it DMR and everyone who lives here calls it Purg...