Lemmy
Everything about Lemmy; bugs, gripes, praises, and advocacy.
For discussion about the lemmy.ml instance, go to !meta@lemmy.ml.
A hashtag fits more for communities than an exclamation mark.
I think it has more to do with the federated nature of the platform. If you are ingesting content from Mastodon for example, # is a hashtag in a post, and you can tag someone with their username with the @ symbol.
Edit: you can tag people here with @ too - such as @knova@knova@dartboard.social
So that leaves a new symbol for community linking
A hashtag for community seems much better than an exclamation mark.
You already said that
But you didn't say why Lemmy does not use hashtags for communities.
I explained that hashtags use the pound symbol already, and usernames use the @ symbol. Communities needed their own symbol.