Cool

I tested/wrote about it recently, you're welcome to copy my metaphorical homework if you want

Friendica Side

(I'm getting an Nginx error trying to load Nerdica, hopefully it'll be back up soon)

Lemmy Side

Cross Compatibility portion of blog post

The long in the short of it is that Lemmy can communicate with Mastodon & Friends, though since Activity Pub servers handle everything and microblogging platforms have no clue what Lemmy is doing there's a bit of jank.

You can post to a community by "@"ing it, although it can only be a text based submission. You can follow a community by following it's name (say @fediverse@lemmy.ml) and you'll get submissions in the form of boosts/reposts. You can also grab a link to a post or reply and search for that on a microblogging server to reply to or like.

My test went pretty well, although the post I made was slightly wonky (title and "@" appeared in the post text). I also didn't see all the Lemmy replies make it back to my home server. If nomadic identities make their way to activity pub most of the jank could be resolved.

As for a testimonial about compatibility something that sticks out is cross compatibility between Activity Pub, Nostr, and AT (BlueSky). I'm usually on Nostr, but I follow Activity Pub and AT accounts; and thanks to a copying of a json file you can search out the same username on Activity Pub or Nostr and find my Nostr account.