lol okay here me out, I am enough capable of looking up info on these communities myself through probably one or two web engine searches, but then again we also have to consider that:
It is a funny title.
I keep forgetting it.
So really though, what I wanted to know was are we able to communicate with people on the *don instances?
So you may see comments or posts from Mastodon users who have posted to Lemmy, but if you want to follow Mastodon users you'll need a Mastodon account.
There is a middle ground. Mbin allows you to participate on both Lemmy and Mastodon.
I tried following Lemmy users on Mastadon. It was a cool to see that it's technologically possible, but it was not a pleasant way to consume Lemmy content.
You can also help #Mastodon visibility / discoverability by adding #hashtags. #Mbin even has a hashtag field on thread creation for this but #Lemmy in one of the more recent updates added general #hashtag support as well.