I'll tell you what a private message should not be, just to shorten this: it is not (or should not be) forwardable.
For the record, the scenario that the parent commenters are describing (which is already possible) is to copy the message into the clipboard, paste it into a new message, and use the 'multiple recipients' feature of specifying multiple names separated with comments to send that message to others. Since the message system doesn't distinguish between 'replies' and 'new messages', it's basically the same thing. From a purely technical standpoint, adding this feature wouldn't make any difference.
In other words, for a message to 'not be forwardable', the Dreamwidth code would need to check the contents of the message to make sure that the message you're sending doesn't contain content from any message you've received previously. Obviously, that's not going to happen, because it would be an artificially silly restriction.
Now, from a social standpoint (disregarding the fact that anybody who really wants to can just send a new message anyway), I can see where you're coming from about not having a forward option. Not having that option would mean that the other person would have needed to specifically use a new message, which will at least mean that they would have had to think more about whether that's a good action.
In the end, I'm against this suggestion, but not for that reason; I'm against it because I think that PMing isn't really supposed to be a replacement for email. There are better tools available for the job.
no subject
For the record, the scenario that the parent commenters are describing (which is already possible) is to copy the message into the clipboard, paste it into a new message, and use the 'multiple recipients' feature of specifying multiple names separated with comments to send that message to others. Since the message system doesn't distinguish between 'replies' and 'new messages', it's basically the same thing. From a purely technical standpoint, adding this feature wouldn't make any difference.
In other words, for a message to 'not be forwardable', the Dreamwidth code would need to check the contents of the message to make sure that the message you're sending doesn't contain content from any message you've received previously. Obviously, that's not going to happen, because it would be an artificially silly restriction.
Now, from a social standpoint (disregarding the fact that anybody who really wants to can just send a new message anyway), I can see where you're coming from about not having a forward option. Not having that option would mean that the other person would have needed to specifically use a new message, which will at least mean that they would have had to think more about whether that's a good action.
In the end, I'm against this suggestion, but not for that reason; I'm against it because I think that PMing isn't really supposed to be a replacement for email. There are better tools available for the job.