I can imagine there will be improvements for SEO in the future, but for right now, being in beta, it kinda makes sense that it would not want to be so very visible.
In the meantime, there is also Search-Lemmy.
Everything about Lemmy; bugs, gripes, praises, and advocacy.
For discussion about the lemmy.ml instance, go to !meta@lemmy.ml.
I can imagine there will be improvements for SEO in the future, but for right now, being in beta, it kinda makes sense that it would not want to be so very visible.
In the meantime, there is also Search-Lemmy.
Since all posts/comments are public, all you need is some kind of indexer to organize them and a list of all the instances. There are people working on it right now. But in the meantime you can just add (intext:"modlog" & "instances" & "docs" & "code" & "join lemmy")
to your search queries to search all Lemmy instances.
They are very low in the search rank but I have noticed that when I search lemmy specific topics I do get "posts" from various instances in the results.
So it seems they can be indexed at least by google but I think the project could benefit from some SEO work to help community discovery from search.