Uwe wrote:

I have a lot of experience moderating forums, and I can tell you that the vast majority of those who join them are lurkers, people who like to read the posts and glean information from them, but for some reason lack any desire to contribute. It's a completely normal situation. Why they don't contribute is open to speculation: Maybe they're shy, or lack the required self-confidence to participate. Why they register might be easier to explain: Most forums require you to be a member and be logged in if you want to see any of the images that are containd in posts.

Ah. That could be the missing point: they assume they need to register to see all content. Not apparently the case here, but they may register first on that assumption.

I miss the pleasure of educated forums as I missed typewriters, but I shall try to restrain my comments here to those somehow vaguely connected with typewriters! Your moderation is effective, and I have not seen the hint of a troll or a flame war cropping up...

Thank you for your patience.