I'm really hoping the folks coming from Twitter soon get out of the habit of long threads of 280 character snippets.
Mastodon's default limit is 500 characters, but instances can have their own (often higher) limits, and ActivityPub doesn't specify a limit at all.
But also, if you're hitting those limits: would a blog post, article or paper be better?
Threads do have a purpose, but they don't get the same algorithm-driven engagement here that they get on Twitter.
@OpinionatedGeek I’ve seen suggestions that the first post in a thread can be marked as Public, and subsequent posts can be marked as Unlisted. This allows the opening post to appear on timelines (like an abstract), but the remainder of the thread will not clutter a timeline, though can still be read by viewing the initial post.
@OpinionatedGeek just watch out for the 140-gauge folks from the early days!
@mo Yep, and that's useful! But people seem to be writing in 280-character chunks, and that reminds me of the myth of railroad gauges (https://www.snopes.com/fact-check/railroad-gauge-chariots/), that simple decisions made for one set of circumstances can carry over for centuries.