I finally found how to follow people and post comments outside my registered domain. For some reason it posted the comments twice. I do not know if that has to do with deleting and reposting.

Two ways.

1 Following: Search for their name while in your own domain or more specifically their at symbol...

2 Copy your name or more specifically your at symbol..... as an answer to the question they ask you when trying to follow or comment on them in their domain

domain might not be correct word