The problem is this. It's easy to do when it's only 1 message in the topic and a couple users. Here's where I can't quite figure out a solution on this one.
Say, you have a private message with 5 people participating, and there has been 15 posts in the topic.
User 1 has read them all
User 2 has read the first 10
User 3 has read the first 3
User 4 has read the first 12
User 5 has read none
So some of the users might have read posts by others but not yours, or vice versa. Or they may have read one of your posts but not all. How do we go about displaying who has read what? We do care, but it's a bit more complicated of a system than UBB.classic.
