[miguelbemartin]

There is not monetary model behind the community. If you read again my comment, you will see that the intention is only to maintain the operational costs by everyone together and a fee is way of getting commitment from everyone.

I basically organise the community because I enjoy reading books and sharing opinion with other professionals, that's it.

[kerkeslager]

I hear what you're saying and I genuinely believe that is your intention.

But your execution doesn't match that intention. What you have created is a business. You're talking about "commitment"--that's a business concern. "Sustainability"--also a business concern. I've had plenty of rewarding conversations about engineering books with people who I never saw again, and I've gained a lot of knowledge at book clubs that no longer exist. A lot of that knowledge came from people who only showed up once.

What you lose when you demand commitment and sustainability, i.e. a business model from your book club, is spontaneity and diversity. The kind of guy who commits himself to a book club every week for years is going to miss the life experiences that give context to his work. It's how you end up with solutions that are perfectly engineered to efficiently do the wrong things.