Unfortunately, long posts are also bad at crossing inferential distances. One reason is that if a post is long people will have forgotten the first half of the post by the time they reach the end. And the longer a post gets the more likely it is people will focus on a small detail instead of the bigger picture. Not to mention that it's more difficult and time-consuming to write long posts, so quality will suffer.
Bite-sized posts that have only one thing people should take away from it are much less likely to be misunderstood. And they can still can still teach people something or change the reader's mind, if only by a little bit. And if there is a missing dependency (e.g. how does a quantum circuit inspector work?) then that can be the subject of another bite-sized post.
You can of course persuade people by throwing lots of text at them. For instance long form sales copy converts insanely well, but there's some dark-side epistemology going on there. Ultimately people have to stop, think, and process all the inferential steps between A and B. There's no way around that, so you can't bridge a big gap in a single long post.
As for the rest I think it's mostly a matter of good writing. Use simple words instead of complex ones. Avoid adjectives and passive voice. Prefer short sentences. Make it clear what you're arguing and why. And keep it terse and to the point.
The synthesis obviously is writing sequences of terse posts. If you need to explain a quantum circuit inspector, do so in its own post.
I like posts that are concise and to the point. Posts like that maximize my information/effort ratio. I would really like to see experienced rationalists simply post a list of things they believe on any given subject with a short explanation for why they believe each of those things. Then I could go ahead and adjust my beliefs based on those lists as necessary.
Sadly I don’t see any posts like this. Presumably this is because of the social convention where you’re expected to back up any public belief with arguments, so that other people can attempt to poke holes in them. I find this strange because the arguments people present rarely have anything to do with why they believe those things, which makes the whole exercise a giant distraction from the main point that the author is trying to bring across. In order to prevent this kind of derailment, posters tend to cover their arguments with endless qualifications so that their sentences read like this: “I personally believe that, in cases X Y Z and under circumstances B and C, ceteris paribus and barring obvious exceptions, it seems safe to say that murder is wrong, though of course I could be mistaken.” The problems with such excessive argumentation and qualification are threefold:
By contrast, terseness makes posts more readable and makes it less likely that the main point is misunderstood. So if we as a community could just relax the demand for argumentation and qualification somewhat, and we all focussed on debating the main points of posts instead of getting sidetracked, then perhaps experienced rationalists here could write nice and concise posts that give clear and direct answers to complicated questions. Instead, some of the sequences are so long and involve so many arguments, counter-arguments and disclaimers that I feel the point is lost entirely.