Mentions and links.
Webmaster here 
We don’t have a feature that supports directly what you want to do. So you’ll have to improvise a bit. Mostly being a bit off-topic does not really matter here, as the Edgeryders platform is even tuned to the “naturally social, 'bit messy” content If you feel sth. really does not fit in, just post it in a thread where it’s more appropriate, or even create your own post for it. And then to @mention relevant user(s) from the original thread whom you want to take notice that the discussion moved – the system will send them an e-mail about the mention (Hi, @almereyda ). Where context is needed, you could place a link to the original thread / comment.
Update: Nadia referred to this one: Edgeryders Dev & Testing group / project.