@foxmask, I still don’t quite get how Mastodon works. I have an account and I’m logged in on https://mastodon.social/ however when I try to answer on this particular post, it tells me to login, and I can’t because I don’t have an account on https://theres.life
Does that mean I need an account on each of these Mastodon sites? or am I missing something?
Ok I figured it out. One button to reply was asking me to login to theres.life, which wouldn’t work, while a different button is asking me for my username@host name, so this one worked. I guess they should make this more consistent and only ask for username@host name when interacting with other posts.
pressing on the button reply should do the trick and notify @theotherguy@on_another_mastodon_instance.tld
weird 
Yes that worked. There's another button titled "Login to reply", which is what I was clicking on initially but this one can't work without an account on theres.life
Ok so too sad for them 