It's interesting that you are occasionally percieved as an "expert" because of your participation in a certain activity by those who don't participate in that activity.
My family substitutes "nerd" or "geek" for "expert", but it all means the same.
I got a call yesterday from a friend. He said that one of his co-workers was signed up to race in an upcoming sprint triathlon, but didn't have a bike. He immediately thought of calling me to see if I would be willing to answer a few questions.
I talked to his co-worker, and gave him my suggestions on what to look for (he was looking for a used bike on Craigslist and KSL), and what to avoid (any bike named after a car, i.e. GMC Denali)
I'm sure many of us who consider ourselves cyclists can relate to the phrase "I may not know art, but I know what I like" I by no means consider myself an expert, but I know what I like, and I know what I've used that works. I guess that makes me an expert of sorts to those on the outside.