How about a view conversation with [username] feature for PMs, too? Like the ones available for VMs. I reckon it'll be a lot more convenient to look at the whole conversation with the PMs sent and received than sort through each related PM from your sent box and inbox, as well as it being a lot easier to reply if a reply dialog box is implemented. Some PMs are a lot more like posts though, so maybe the conversation could look more like a thread does normally for it to work, with each PM being a separate post. It's like seeing your PM conversation as a personal, private thread where you two post replies to each other.
To extend that metaphor even further, maybe these personal, private threads can involve more than two people so that you have a thread of your own that doesn't make the forum look unpleasant (with the possible off-topic/irrelevant/random content present in a lot of VMs). That sort could cater to as many people as you'd like. I'm kind of grasping at straws here, though; but at least I think it sounds like a nice concept.
Anyway, the main thing that I'm kind of suggesting is all in the first paragraph. I don't know the feasibility of this suggestion, but yeah I'm curious if this is at all possible. Again, this is probably not possible with how vBulletin is structured but I might as well suggest it here.
EDIT: tl;dr first paragraph talks about implementing a view PM conversation with [username] feature, while the second paragraph talks about making PMs more like threads, which in turn, can allow more than two people in the conversation. I can understand why the post can be confusing, so I apologize.
I'm all for this, but I sure hope other users who are not involved with the PMs do not get the option to view others' conversations. For example, I don't want so & so viewing my conversation with what's his face. That is the whole point of Private Messaging. But, if this is an option only for either of the two conversationalists, then I think this is a good idea.
“Our only limits are the ones we place on ourselves.”
I kinda like this idea because when some one you PM'ed doesn't quote you and like me forgot what was said you have to say "what" it is annoying that way, but I would want any one else to be able to view the convo at all.
I've always wanted something like this, especially since if it's a similar system as with Visitor Messages - just not public. I hope something like this is possible. Though, the thread prospect might be pushing it a little? I mean, I think there was a time that PC had public groups where people could come together to talk in such a way, and though it wasn't private it was similar, but that was a built in system. I'm not so sure something quite as elaborate could even be done? Regardless it's a cool idea.
I'm totally down for this. the quote boxes aren't bad. But if you're having a conversation with someone, it can look chaotic and messy. Something like this could make it a little neater. The current system isn't terrible, though, I'll have to admit. But this would make a nice variation.
So what I got:
1) "View PM with X" link like their is with VMs
2) Make PMs like a thread instead of quotes.
I'm not sure about the first one, as their can be different PMs. Wait thats what the thread-like suggestion would fix.. but what about multiple people convos, no link for those, and different threads? Confusing post but I'm all for the idea.
I know a few other forum softwares that use this type of feature, except it's slightly different. You can view the history of one topic instead of with a specific person, but it follows the same idea of it being almost like VMs except private.
In fact, what I'm thinking of for forum software that does this is Xenforo. It's my favorite PM system by far, and having it here would be wonderful.