Frolf bugs me and makes me laugh. It's best used as a punchline by people who know better.
I agree with the post suggesting that "Frisbee" is a word much like "Kleenex," "Xerox," or "Band-Aid," where the trademarked name became so synonymous with a product that the trademark name and the non-trademark name are synonymous in most people's minds.
Think of it like this: if Wham-O didn't own the word "Frisbee," would we have ever started calling these things we throw "discs?" -- probably not. We would have stuck with the word "frisbee" (notice the lack of capitalization) because it is a unique word that to the popular mind describes roughly-flat, circular, plastic, hand-thrown flying objects that exhibit properties of lift, glide, etc...
So I will never get offended when people call something "frisbee golf," because that's the most obvious, easily-understood term for what we are doing. At some point, usually with humor, I'll give people a little context for why serious players call the sport "disc golf," all tying back to the history of flying Frisbe pie-pans and Wham-O patents, etc... but that's just a little too disc-nerdy for an opening conversation with someone about the sport.
Get 'em hooked first, then bring out the history.
But yeah, "frolf," -- it just makes me laugh because all I can think of is George Costanza. And Costanza ALWAYS makes me laugh. He's that guy with the totally absurd (but believable) life that always makes me glad to be ME and not HIM. George just makes me feel better about myself.