This was brought up as a request in the /c/autism community. The idea is that post can be flared with a tag that categorizes a post, telling users what type of post the user made. The flair would appear before the post title. In the case of /c/autism, the categories could be meme, discussion, venting, seeking support, education, question, etc. This would allow another user perusing the community to know if the post is worth looking into. www.reddit.com/r/autism has some good examples.
It’s frequently requested, but not a feature of Lemmy yet. I wouldn’t necessarily expect new features to get much attention for a while, as the rapid growth has made really big problems for admins and mods with technical performance and community management. They’re almost certainly going to be focused primarily on scaling and mod tools for a while.
But if a community member steps up, I expect the devs would merge a well-crafted PR adding flairs if someone submitted one in GitHub.