Hashtags do not replace groups.
No one moderates them. They’re easy to hijack and spam. And there’s simply no permanence to them.
Which is why, if you actually want to discuss something, it’s better to tag a group. For example, if you want to be part of an actual PC gaming community on the Fediverse, it’s better to tag @pcgaming@lemmy.ca than #pcgaming.
This needs to be common knowledge because people new to the Fediverse do not know about groups. Hell, I’d say people who have had Mastodon accounts for years still don’t know. And that’s a shame.
@fediverse@lemmy.world
The mastadon user posting the thing needs to tag the Lemmy community in their post and then it will show up like any other post on Lemmy. You wouldn’t even know it’s from Mastodon unless they said so in the post.
You can usually tell it’s from Mastodon because it’s got a couple dozen hashtags scattered throughout the post and a dozen more users and communities tagged.