FOR ME, it was something i acquired for free- an extensive continuing education on audio as well as what people enjoy listening to. i especially enjoy the pictures which help to answer alot of my questions (as well as raise others). lately i have been doing a bit of research on how (amazingly) well mid-fi equipment sells on this site- it appears that many individuals are pleased with inexpensive equipment, especially as long as it has been well cared for.
i also perceive a trend buying equipment that alot of people expressed enthusiasm for in the forums, whether it's new or several years old. a preamp, for example, that sounded superb 5 years (or more) ago, still sounds truly wonderful in 2007. a VTL-S150 amp is just about as nice a tube amp as you can buy regardless of price; this fact remains constant through the years. so while stereophile is obligated to "move on" (unless it's a Linn LP-12) in their recommendations, audiogon is far more informative, as long as the reader is really paying attention. ALSO, one must remember that a $2000 pair of speakers may be prohibitively expensive to some people, and we should never be snobbish about those who would still like something nice- perhaps all they can afford right now might have to reside in a dorm at college, or a small apartment. a friend of mine (i kept my mouth zippered shut!) put his dinky bookshelf speakers on the floor pointing at my ankles! but, he introduced me to a guitar genius named "Blind Blake" whom i acquired every alblum of his that was available. plus perhaps they may know alot more about music than you do, and/or make their living playing or teaching an instrument. audiogon is not just a marketplace for equipment, but a often becomes a community of people who love the arts, so with mutual respect for the preferences and opinions of others, you can end up with a nice system, some great tunes, and some new friends.