Yes and no.
The longest-established discussion systems are Guppe groups and Chirp groups, which are basically accounts you follow which repeat anything sent to the account. It's a very simple system but these can have quite good conversations on them. More info at https://fedi.tips/how-to-use-groups-on-the-fediverse/
Mastodon itself is working on Mastodon Groups, but this isn't ready yet. This seems it might be more like Facebook Groups?
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