Well both have threads in different communities (reddit subs vs. boards like /b/).
4chan allows posting without an account, that is why it is popular for leakers, whistleblowers etc…
4chan “post comments” are chronologic, reddit post comments are nesting and have various sort orders. I think Reddit is objectively better here in my opinon, so I would just ignore this difference and do it like Reddit/lemmy. But if you really want you can give communities power over this.
4chan threads are automatically deleted after a short while, so they basically have pruning. This is a bit complex to explain, but I don’t think the exact mechanism is that important, as long as threads are deleted after a while. That is one important feature of 4chan vs Reddit where everything is saved.
The most important point is that everyone on 4chan is anonymous by default. I don’t use 4chan, but if I rememeber correctly depending on the board: 1) you get a unique ID for the thread so others can identify you in the thread 2) on some boards you don’t get an ID, it’s just that every post has an ID, but you can’t tell what two posts are by the same person 3) You can also give yourself a name on some boards I think. Another level of “anonymity granulatity” that 4chan doesn’t have I think, could be you automatically get a unique ID cookie that expires after you don’t post for a while.
Naturally there also is not post/comment history like there is on reddit.
So what I like about 4chan is 1) posting without an account 2) posting anonymously 3) posting anonymously with a unique thread ID 4) posting pseudonymously without an account 5) thread/comment pruning aka auto delete after some time.
But you could imagine all these various levels of anonymity on a spectrum from 4chan to Reddit. Phrased differently, from posting completely anonymously without an account and everything is deleted after some time like 4chan TO posting pseudonymously and posts stay forever and other users can see your post history like Reddit.
To explain further what I mean by the spectrum between 4chan and Reddit:
In my optimal social network a community would be able to perfectly mimic 4chan.
Or a community could require you to have an account but otherwise mimic 4chan perfectly.
Or a community could force everyone to post under a community pseudonym, so if you have a history on other instances/communities others can’t see it, only your history on this community.
Or a community could allow you to choose if you want others to see your cross instance history or if you want to be community pseudonymous or if you want to be completely anonymous.
Or a community could require you to be completely transparent about your cross-instance history like Lemmy.
And any of those communities could auto delete posts/comments after a while, regardless of anonymity etc…
But all of this with federation like Lemmy. So I can go to the community on a different instance (let’s say test.ml) that perfectly mimics a 4chan board (and requires an account) with my feddit.nl account and all my posts there will be anonymous. My post/comment history on this 4chan-like community won’t be visible in my account history and others on this 4chan-like community can’t tell it’s me.
Lemmy kind of allows you to be pseudonymous on every instance by just making a differnt account for each instance. But that is tedious, I would want to be able to be pseudonymous on an instance/community level with my existing account without having to make a new account. Bonus of this being that admins/mods could ban pseudonymous accounts from certain instances, but not from others.
Basically have various different anonymity/pseudonymity/pruning features that communities and users can mix and match depending on their needs.
Why? Maybe you have cancer and you don’t want everyone else to know you are posting on a cancer community, but you still want others in that community to see your post history.
And in general it’s just good OPSEC/privacy practice to have that kind of separation. It would be amazing to hinder Big Tech/Big Ad companies from mining and selling your data.
I know some people don’t care at all about that, but I value my privacy and my optimal social network would protect is as much as I want.
And anyone who doesn’t like those kinds of anonymity features, because of brigading or hate speech or whatever can just exclusively visit communities where those kinds of features are turned off.
I personally wouldn’t want to frequent 4chan-like communities either, as they are basically the sewage pipe of the internet. I would want something between Reddit and 4chan. But I don’t see why not to let others have their fun in the sewers, so I would let communities and instances decide.
And also would like to have a personal closed off community with my friends, like a Discord server or a group-chat, that I can access with my normal social media account without without worrying about data leaks. So there these features also come in handy.
So yeah I think the optimal social network would let communities decide on these features in a very fine grained manner. And of course combine that with fine grained permissions, who can do/see what and why.
Sorry for this post being so long and convoluted, but I hope you understand what I mean now. It’s just an unavoidably complex idea that I struggle to explain fully and succinctly. But every ounce of that complexity is nescessary if you ask me.