I did a search 'site:lemmy.ml' and a lot of pages came up. 'site:lemmy.world' returns 296 results for me.
I think this could be a problem for the fediverse. I can't make a global search in Google because each Lemmy server has a different domain. If I find a post from lemmy.ml, I can't answer the post because I have an account in lemmy.world, and so on.
Hopefully in time google search would be smart enough to know all the instances of lemmy are all lemmy. Maybe site:lemmy.ml wonβt work but just adding lemmy at the end of a search might
I'm still getting used to this but, I think you can respond to that Lemmy.ml post using your Lemmy.world account if the two instances are federated. I've made comments to posts in communities hosted on instances other than my home instance.
If I understand right, you can respond to a post if you arrive at it through your instance that you're logged in to. If you find a post through Google or another link, you can't just click "reply" - you have to find your way back to the post through your server.
I'm sure the devs are working on cleaning up that experience. Sounds complicated.