I've know miners who are secretive about their mines, the location and how much money they are pulling out of their mines. They will read up and do their homework, but keep quiet when it comes to sharing information.
Then I bet there are a lot of novices that come to this site to learn. Prospecting is a hobby they want to take up someday, but they just haven't found the time, but it's fun to dream about. I know there are a few hobbies that I dream about, but I just haven't taken up yet. For novices it's hard to really add value to conversations if they don't have a lot of experience. They risk coming off as ignorant, and unfortunately people aren't as nice online as they would be to your face.
Also, there is the technology barrier for some. A respectable percentage of people who get into prospecting are in their late 50's to their mid 60's. Many are computer savvy, but some aren't comfortable enough on the computer to join forums, and although they have a lot of knowledge to share they don't participate.