You can have a discussion on anything. A message, a to-do, an event, a file, a text document, etc.
The Discussions section aggregates everything together, no matter where it happened. It feels like the right name to us. It models the world better. You discuss things in person, you discuss things in a project.
That makes sense. I may not have asked clearly, though. Is a "discussion" a collection of one or more comments, or is each comment/post/thing its very own "discussion"?
For example, if I post "What do you guys think about this new feature?" and then you reply with "I think it's an awesome feature.", is there one discussion or are there now two discussions?
The Discussions section aggregates everything together, no matter where it happened. It feels like the right name to us. It models the world better. You discuss things in person, you discuss things in a project.