In reply to Frank's initial post :
So, though it seems a less than prudent idea to make RFF membership a "Credential" in the classic sense, it does make a lot of sense to add your affiliation with RFF to certain documents and communications. Sort of an unofficial credential - just a way of offering someone access to a pile of information that defines your personality, trustworthiness, sense of humor, etc.
When I sell on the auction site, I give my RFF screen name and some mention of the site, so that buyers (or sellers) can access the site and research me. By doing that, I offer buyers and sellers a chance at becoming as familiar with who I am as customers are with their local camera stores - they know who I am, how i think, how i feel about things, how I communicate and lots of other stuff.
I believe that Frank meant NOT that RFF credentials should be posted in a way that suggests their status as something on the order of membership in the NRA (or other nationally recognized organization), but that it could be used to add a deep source of information about yourself. Put it on a business card and give your clients a way to get to know you - if that seems like a good idea. . . .
2 cents