What does your 'home' instance really matter?

Really the biggest effect your home instance has is who you're defederated with. Your instance admin can choose to defederate with an instance at any time, blocking your communication with that instance.
For most instances this isn't a real problem because nobody defederates without a clear reason, but in some cases like Beehaw users were upset that the admin decided to defederate with instances they use.
- I recently signed up and didn’t know where to park myself. So I got accounts on both lemmy.world and beehaw.org.
  From lemmy.world I’ve added to a few of the beehaw subs that I’m subscribed to there. But I can tell you I see different content in my lemmy.world feed.
  Don’t know why. A delay in the content making it over from beehaw to lemmy? But my home feed certainly looks different in both (even subscribing as closely is I can to the same feeds).
  So for now I’ll stick with both and see how the dust settles.
  
  or you can join a smaller instance that beehaw has not defederated and interact with both beehaw and lemmy.world communities
  
  It's because Beehaw defederated with most of the popular instances. Their communities still exist but none of the posts will come through to Lemmy World and vice versa, they can't see any new posts in Lemmy World communities.
  IMO just stick to lemmy world and avoid beehaw communities (they're effectively dead for us) unless you want a "safe space" and live in the small Beehaw instance.
  
  Same here. One when I want to keep it polite and the other when I want a little more freedom.

local filter for posts in communities you're not subscribed to
defederated and blocked - of the instance and from the instance
hosting, updating, performance, uptime, sustainability, risk of disappearance, security, responsiveness on issues
settings, UI, additional hosted tools
rules and focus for local communities
IMO there's nothing to keep in mind on everyday use. But these things are things to consider when deciding what to use in a mindful manner.

Some instances have a tight thematic focus and, if you want to create communities, you should probably do it on an instance where it will be on-topic. That's the reason my main account is on midwest.social instead of the first instance I signed up for: slrpnk.net has a tight focus on environmental sustainability.
- Another important thing to consider is governance and privacy/security. You're trusting the admins to not missuse your data, to not read your messages, and that they agree with you on how federation should work (ex. Who they choose to federate / defederate with). There's also the side of donations and how upfront they are about costs, where they choose to store your data, etc.
  If an instance is being run transparently like a non profit, with good governance and regular updates, then that's amazing. Not all instances can do that

It matters. The admins mater. They control federation, styling, upgrades, security, performance, and admin-level moderation things. Also, some instances try and cater to certain communities (e.g. lemmy.zip tries to focus on gaming and tech).

If your instance goes down, you lose all you posts. vlemmy.net was an instance and they just vanished recently. lemmy.fmhy.ml just disappeared yesterday, I couldn't find much info besides a post vaguely mentioning that their domain name got seized by the Mali government (idk why). Besides being shut down, also due to federation issues. beehaw.org has defederated from lemmy.world and sh.itjust.works, meaning you can't really interact with each other for the most part. Some instances like lemmygrad.ml and exploding-heads.com are disliked by many instance owners due to politics and got defederated so they are sorta on their own island.
Edit: Well... techically, your posts aren't lost, you can still find them in other instances. But your images are gone since images do not get federated (unless someone made an archive) and you lost the account and any direct messages, and you have to manually check if you want to see any comments to a post that you posted before it got shut down. Just a huge inconvenience.
- Former vlemmy user here, was very miffed when it vanished without a trace and with no warning.
  Honestly, I think Lemmy needs something equivalent to the Mastodon Server Covenant.

You could also be in a position where the insurance just disappears.
I joined lemmy.fmhy.ml which has now disappeared, from what I gather they received a take down notice.
So whilst but important which instance in general being with a reputable one can matter.
- So when this happens, you lose all of your posts/ comments/bookmarks?
  
  The comments/posts I made on other instances via that account are still there and i'm guessing will remain so but bookmarks/subscriptions etc. start from scratch.
- Crap, sorry to hear that
- why were they taken down?
  
  Not entirely sure but it was a piracy focused instance so best guess is they recieved a takedown request.
  
  Looks like I was wrong and it appears that Mali has been recaliming the .ml domain that they were using, so hopefully they'll be back. According to the post they have backups etc. so once they sort out a new domain they may be back. Fingers crossed.
- My original account was gone with no warning when vlemmy.net shut down with no communication. I have since made a few backups in case the same thing happens

I dont have my account on lemmy.ml because my opinions do not align with theirs.
Also choosing an instance with servers close to you is a plus as well for loading times
- I do wish there was a convenient way to move your account from one instance to another.
  When I chose my instance I didn't really know what I was doing so I just picked something at random, and unfortunately the instance I picked isn't exactly physically close to where I lived so the load times are a bit slow. Although they're still faster than Reddit so 🤷
  
  You can use this to easily move subscribed communities and bookmarks
  
  Mastodon has a method of migrating from one instance to another. So, I feel it should be possible for Lemmy as well, and should eventually arrive
- It was created by the lemmy devs and ml stands for marxist-lennist

In general it's not that important but there are a few considerations. There have been instances that just disappeared so that isn't impossible. There could be instances that yours is defederated from and that would affect what content you get. Also when searching for communities you might not see things you would be interested in because nobody on your instance has searched for it yet. The first successful search for a community requires you to know the actual community address and then that causes it to federate with your home community so if you just search for a word, like cats, you will only see cat communities that someone on your server is already subscribed to or already searched for.
- requires you to know the actual community address?
  Can you explain that more? What does a community address look like and how would I access one once I know it?
  
  Full disclosure I'm not an expert on this but it would look something like !cats@lemmy.world but I'll go check a community and get a real address for you.
  Edit: that is a real community address so that is what you would need to type into the search the first time, then wait like 5 minutes for it to federate then search for it again and it will come up now.
  Edit 2: since you're on lemmy.world you're going to have access to a lot of content without doing anything special since it's a huge instance.

One thing that might not be obvious is that the All feed is different too, as it only shows posts from communities someone on the instance has subscribed to. But since there are ways to search communities across instances, it isn't really a big deal. Unless you're on an instance of one or two people maybe.
Federation and moderation are probably where the instance matters most. Also, the matter of who runs the instance is kind of important considering stability and longevity of the instance. (mine for example will probably be gone within a month once I break something)

The only way it matters is if/when it is defederated by/from other instances.
That being said, some may or may not be more reliable than others, but that's a separate issue
- That’s not the only way. Smaller instances will have very different All feeds because All is just an aggregate of your Instance-mates.

Largely, I'd say it depends on the sort of engagement that you're looking for. I went with mine because I'm passionate about FOSS and think that, long-term, it's only sustainable by organizations that do not have a profit motive.

If it goes down you can't get on your regular account, but I made a backup account on another server for when that happens.
- A backup account like a second account? Or does your main account back up to the other one?
  
  Like just a second account, I can't be bothered to do anything fancy.

I hosted my own for now :3
Quick plug for any "The Big Lebowski" fans, join us at https://lemmy.world/c/achievers@lebowski.social
- Hi there! The links in your text lead away from the user's instance, here are fixed links that stay on each user's instance: !achievers@lebowski.social

I don't know, but I keep trying to comment on posts federated from other instances and half the time I get some obscure error and it fails, and it's fucking irritating.

Sometimes syncing of comments/posts in communities between instances can be delayed or missing. I noticed some communities on Lemmy.world would be missing posts if I view them from my Lemmy.ca account.
However, these issues aren't as prevalent for me as they were a month ago. I imagine it's been better after the upgrades.