Why YSK: right now, Lemmy’s autocomplete for the !community syntax isn’t working correctly.
It will appear to work, like so:

But the link produced will redirect you away from your home instance and leave you unable to vote/subscribe…

To fix this issue, you’ll need to manually edit the autocompleted link like so:
BAD LINK: [!youshouldknow@lemmy.world](https://lemmy.world/c/youshouldknow)
⬇️⬇️⬇️ Remove the domain (i.e.: https://lemmy.world) & append the @ identifier (i.e.: @lemmy.world)
GOOD LINK: [!youshouldknow@lemmy.world](/c/youshouldknow@lemmy.world)
Removing the domain like this transforms it into a local link which prevents the instance redirection. Doing this will make it easier for newcomers to join your community and participate in discussions!
Those interested can monitor Github issues #369 & #1048 for when this UI bug is fixed!


Unfortunately, no. For posts/comments, there’s currently no way to create cross-instance permalinks. You can follow progress on fixing that issue via Github #2987.