addison

From my understanding, it's an indicator that differentiates Lemmy links from email addresses.

If you follow the link conventions, !technology@beehaw.org should link to a Lemmy community, rather than open a new email compose window.

You don't have to create an account on the instance to subscribe to their communities.

You can, for example, search for !programming@programming.dev to index that community from your home instance.