I have tried many forum-styled site over the years including the politically more questionable ones, and from what I see theres 3 hurdles a site need to pass in order to be good:
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it needs good infrastructure, especially user interface (where 4ch, most forum, and now reddit fail)
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it has some gatekeeping to filter out the "order consumers", but not too much that it drives user away, including having a toxic environment (where 4ch and .win fail)
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it needs to have enough user generated content so thay theres actually reasons to use the site (whre most reddit clones fail)
from what I see lemmy has passed all the hurdles, and I have good hope the fediverse will stick around