My business over the years has led to relationships and sources of gear too good to pass up. I took it upon myself to ride the roller coaster, sometimes making money, other times coming out even, occassionally behind.
I recommend looking at how the person posting relates to the item. Are they talking about it like it's the "best think ever like an eager puppy?" Do they have a history of 10,000 posts drooling all over themselves and acting like an authority? Are they just trying to talk it up before they post it for sale? Are they always disgruntled about what they are posting? Do they just want to interact with members because this is what the hobby means to them- more community? So many more perspectives to consider .
I find it helps to assume that most have less of idea of what they are talking about, and out of those, most will have different tastes. From there it really helps to have a shared vocabulary. Even better is if the poster has heard something that you have heard so you can test that vocabulary. It takes time and experience on all sides.
I have a dozen or so audiogon friends that I interact ocassionally about gear. Some of them have owned things that I owned years ago, and others have moved up to the next level or several levels from what I currently have. Some you will clique with more than others, just like any area of life. One thing I've found useful is to reach out via PM if there is a question you want to ask someone. Sometimes you can get great information "off the record". I don't think any of us likes really slamming a product on the forums- these guys have families and rent to pay. Off-line it is surprising what you can learn. Realize dealers have heard all the other items BUT what they sell is clearly just better. lol
Quicky, the room. I once had a perfect, well treated symetrical room. Now I have my system in a living room. Be careful with guys that know it all but have poorly set up rooms, like mine.