I was wondering whether that could cause issues for the limited servers available, like when the mass migration from reddit happened.
Would it be bad to add more accounts that would be mostly dormant?
And if one does create a throwaway would it be better to delete the account afterwards.
If it's to protect your identity from some embarrassing content you're afraid of tying with your main account then it's fine.
If it's to skirt the rules of a community or instance then you're just pushing the instance admins into making it harder for everyone to make throwaway accounts in the future.
It would add some extra rows to a database, which can increase lookup times if enough people do it with enough accounts... so from a general engineering perspective, I wouldn't encourage it.
In a more realistic sense, it would take a lot of people and/or a lot of throwaways to effect much difference. That is, assuming the database queries aren't too complex or inefficient, and the servers aren't nearing critical capacity.
Deleting the account afterwards may not be as effective as never creating the account altogether. There's a chance some stuff is only tombstoned instead of deleted, things get stuck in caches too, it would probably be better than keeping the dormant accounts though.
Tl;dr It would be polite of you to keep only a couple of throwaway accounts, but I wouldn't feel too guilty about making them. Just don't be like a spam bot and create dozens or more.
I think that the impact is rather small. The major issue is actual usage; a dormant account won't tell the server "please fetch me those resources", or "please send this comment", or stuff like this, it'll be at most a new line in a user database.
I imagine if it becomes an issue for the hosts of the account, they can just delete abandoned accounts, or accounts that havent interacted in some time.
I have an account in ml and another in lemmyworld. I like ml much more, but created the lemmyworld one when ml was having down times.
I don't think it'd cost the server much storage or computing power, but it would probably mess up an application queue. Also hopefully the instance does inactive account purges every so often.
This isn't a throwaway account per se but I do have another account on lemmy.ml for interacting with other communities. This account (and this instance) is focused on free software and free culture advocacy. It's not really about embarrassing behavior, but more about compartmentalizing interests.
A valid use for a throwaway would be to ask a sensitive question that you don't want to be traced back to any of your main identities. This would be a question that is asked once, answered once, and never revisited again. There would be no need for it to be associated with any of my identities.