Stop blabbing about such and such while I'm trying to putt. Have your conversation later.
The other thing that gets me at our course is people who just yell "Fore" all the time. Don't just yell it when you are teeing off because you are going to throw on somebody. I just ignore it mostly because I hear it every two minutes. And don't throw until I've finished the hole. Better yet when you do yell give a specific like "Heads up on 5".
An article on disc golf etiquette is a great idea, but I would like to see emphasis on the fact that etiquette is relative to where you play, generally by region and who you play with--while there are certainly rules that can be applied to all regions (such as farthest from the pin putts first, he who wins the last hole has the box, etc) but some are only observed in certain locations (such as radios, vast consumptions of libations, chatter at any time, etc)--to take it a step further, etiquette changes due to who you are playing with and the level of competition involved--how casual is casual? Should etiquette for any given round be established at the 1st tee?
I would like to hope that our counterculture sport does not have specific set of etiquette, with tournaments being the obvious exception...
Keep the group size to four. Counterculture sport or not, keeping the course flowing is key. The vast majority of discers have no desire to see folks getting off on mother nature in groups of six or eight. And if you are in those big groups let folks shoot through.