I was thinking that it may be a good idea to allow non-registered users to view forum categories so search engines can index these pages allowing people to find this site (and its information warehouse) through keyword searches. There are many forums out there that do this and I don't really see it as a problem.
Sounds like a good idea to me, make it viewable to non-members but you have to be a member to post.
Actually that's how I wound up in the group. On a whim, I searched the net for my name and I found it on the comicspriceguide site. When I checked, I found that OM mentioned me and I joined the group. Since then, on other searches for specific ugs, I have been Googled to that site. Never here. If you want a larger membership, people have to find you other than by word of mouth. You might also want Fogel to mention the site in the guide.
I often turn up old, underground-related posts from CPG through my various Google searches, though nothing here, which led me to suggest opening up the view to non-members.
I see that Google has already begun indexing now that the forum has been opened up! I did a string search for "Tebeito Fino" (http://www.google.com/search?q=%22Tebeito+Fino%22&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a) to test it.