Requested feature overview description.
When responding with dmails, right now clicking respond will quote all everything. Instead, it should only quote the last message received without the previous messages quoted. If someone needs to see all messages in the given discussion, we should rather get back similar button from old site which would fetch all dmails of that exchange.

Alternative would be to have dmails act like forums, where with responding, all of the messages of that exchange is on single page.

Why would it be useful?
This is in contrast with forums and comments where only the message itself is quoted and previous quotes in that quoted message is discarded.
Pyramid of quotes can get extremely high with people who do one sentence dmails back and forth and users editing their dmail before sending to get rid of that can break the dtext, making reading their respond harder.

What part(s) of the site page(s) are affected?
Dmails.