Those were all isolated places, where you needed an account for that specific forum (whereas you can use your PDS anywhere), where that forum held your data (whereas you hold your atproto data, and we all internetwork to see the aggregate), where you were subject to the moderation decisions of that forum (whereas you have control over your PDS (but not other people's clients)).

Pretty unclear what your comment is trying to indicate but it sure feels very different to me, and I've offered some characterizations for why.

More generally, atproto is useful for all kinds of tech, solves a cold start social network problem. Aren't we reinventing forums, and tv watching, and book reviews, and trail maps, and photo sharing, and streaming, and d&d, and key attestation, and file sharing, and publishing, and note taking and containers and git hosting? Yes. Yes we are. https://atstore.fyi

(Under a common protocol set, in a way that respects users unlike everything else that's happened online so far.)