As mentioned above, the reason there is so much disagreement about what music is progressive and how progressive it really is, is that the term is used to describe many ostensibly different styles of music. Many innovative and unclassifiable musics are included under the progressive umbrella, which leads to a lot of confusion. So, regardless of how you feel about labelling and the boundaries of the term, when you read r.m.p., keep in mind that many people reading the group many be coming from a completely different musical background, and may be listening for different reasons. The term is absolutely not limited to early Yes and Genesis. People who think this tend to be very surprised when they first hear Henry Cow, Magma or Univers Zero.
Progressive music is that which is discussed on r.m.p.
If you can appreciate this without thinking that I am making any claims of eminence for r.m.p, then you understand the state of play I think. You need a CD player. Most re-issues of lost music and most new releases are produced for CD only. Personally, I have spent a small fortune since discovering r.m.p and the area in general and I consider it some of the best investments I have ever made. Do not be intimidated by people with huge collections, encyclopaedic knowledge as r.m.p is a friendly place where the overriding concern is to promote the enjoyment of some of the finest music ever made that you would simply never otherwise hear about.