Does something like this exist? As far as I can tell, setting something similar up would require:
- A dedicated Lemmy instance for Mastodon tag-based crossposting (probably, since most existing instances probably don’t want to clutter their instance with thousands of script-generated communities)
- Some kind of form on a site where users who want to follow a Mastodon tag that is not already set up as a Lemmy community could submit the tag they want added, which would automatically set up:
- A Lemmy community for that tag on the aforementioned instance, and
- A Mastodon hashtag bot that automatically crossposts all posts with that tag to the linked community
The kbin equivalent, which is baked in to the platform, is that communities would be able to define a set of hashtags that get cross posted into their community. So there wouldn’t need to be new communities.
The main issue though is how do you meaningfully cross post mastodon content to lemmy? Will we be able to see the replies from mastodon users? Will we be able to reply?
If lemmy users are happy to treat mastodon posts like any other external content, it could work well. But more than a bot would be necessary to fuse the two platforms.
That already happens. Non-lemmy users can post to lemmy by making a normal post that @-mentions a community.
Yes, but we’re talking about a bot doing this according to the hashtags in the post. The original post, having never been posted to a lemmy community as you describe, can never be interacted with by lemmy users even if a link or cross post is made.