Other than that... meh. The memes, piss-taking and toxicity make them all but worthless for anyone who wants to have an intelligent conversation.
Places like 8chan, Lainchan, Postbox, etc. are awful. 8chan was cool for like 6 months because it had all of the tinges of old 4chan, but it got co-opted by different groups until it became the alt-right hugbox. Lainchan is just filled with a few different caricatures of previously-underage or mentally unsound 4chan /g/ posters. One thing they all seem to have in common is pretentiousness and a burning need to constantly participate in actual - not humorous - one-upsmanship; they must always be better than the "normies" (an irony here being that they use the new-school "politically correct" version of the parent word) and even the people they deem "worthy" of participating in discussion. They often make spinoff after spinoff, IRC channel after IRC channel, and then cry about having no place to discuss what they want despite having a wasteland of dead spinoff boards and IRC channels. Point out that they're free to discuss their topic on $theLatestSpinoff, and they'll cry about whoever isn't part of their in-group "ruining" their space. It's tiresome and they're not worth any nuggets of information they may hold.
There are one or two up-and-coming imageboards that actually have amicable content and decent users, though.
I miss the feeling I had about the internet when discovering 4chan a decade ago...
I mostly lurk. And It's mostly for "the lulz". But once in a while you get big nuggets of wisdom and insight. It's "a thousand monkeys in typewriters" in practice.
I find imageboards to be interesting from a media-studies perspective, though. They're a clear case (even clearer than twitter) of design influencing user behavior in a way that eventually generalizes outside of the platform. Three countries have shockingly similar & arguably totally distinct right-wing authoritarian populist movements that sprung up from totally distinct popular imageboards during the same period, & there are probably more that I'm simply not aware of. So, serious study of the kinds of behaviors imageboards encourage & highlight (and serious study of under what conditions those behaviors generalize) is potentially really interesting. It's one of those things that makes me wish I was a real social scientist instead of just a programmer with hobbies.