Sorry Ekistler sj. I was just being playful and not attempting to answer the question in a serious manner - it was an effort to create a Seinfeld type of dialogue more than anything.
When writing emails, I commonly make references such as:
I have a question concerning your ad at Audiogon... or
There is an excellent thread that recently appeared on Audiogon...
Either way works for me, but definitely not "in Audiogon"