There is an argument to be made that something like this SHOULD be somewhat exclusive - otherwise, to a lot of people, what's the incentive to participate? You know, that whole Groucho Marx "I wouldn't want to belong to any club that would have me as a member" thing. There would also be nothing to stop a drive-by joiner from posting a few comments to the threads, creating some gallery postings, and submitting work to the book. That would be terribly unfair to those who have been long-term participants and contributors, and not representative of the APUG community. If you must allow members and not subscribers, allow members to submit, but subscribers get priority in the book. If there are not enough subscribers juried in, then allow members to be considered for the remaining slots. I don't think putting labels like "subscriber" or "member" would be that meaningful, especially to the world at large that would see the book. I would put a bit in the bio for each photographer how LONG they've been an APUG member - "joined 2002" etc.