Some what like the old confirm when read vB has. But more facebook wise rather then a conformation. On facebook, if you read a PM but don't reply, the indicator image changes and below the message you then receive a stamp.. Seen 3:04am Would be great to add the Seen to PCs, help know that messages not requiring a reply were at least read
I've mixed feeling about this one. Kind of like having a cellphone: you don't want to talk to someone calling but you know they know you saw their number come up in caller ID and you'll have to deal with their pissy attitude if you wait too long to get back to them.