A french forum I've been heavily involved with for the last 14 years used to require a proof of ID to join (for both reading and posting) for a decade. However

A french forum I've been heavily involved with for the last 14 years used to require a proof of ID to join (for both reading and posting) for a decade. However members were still pseudonymous once approved. In my opinion it had two substantial effects: - A substantial improvement in the quality of the discussion in the short term. No spam anymore, few low-quality writers, and the fact that users enjoyed privacy but not at the expense of accountability made for lots of interesting discussions. - Almost no new members because of the reading barrier, which caused a slow but significant decrease in quality in the long term. While this private tight-knit community had a good run for a decade, once in a while an interesting member would leave for life reasons and at some point the lack of a new guard posed an existential threat to the relevance of the forum. Both of these facts led the staff to reenable enrollment without an ID a couple years ago but still keep a private subsection with ID required. We had an influx of new members (as we expected), a few interesting ones among them (as we hoped). Personally I think experimenting with anyone-can-read + writing-requires-ID could also be worth exploring.