I also think in many cases if you are looking to buy a most likely high ticket item you should know what it is, its specs and how it performs because you should have already been doing extensive homework.this is true, you should, and many/or most people do by the time they see an ad. But what about those who don't? Does a seller want to miss a potential sale because he/she couldn't say "this is a x widget and you can read up on it at this link to the mfg website".
Further (and this is the stupid part), why say "if you're reading this"? If I'm reading this, then OF COURSE, I'm reading this. And how does it follow that I know all about the item BECAUSE I'm reading this?
I have purchased Audio gear that I found through a used equip ad both here and ebay and I previously knew nothing about, but since the ad peeked my interest, I spent the time to learn more about it. I have also sold gear to individuals who were in the same situation prior to seeing my ad.