Exclamation Mark in iMessages Sometimes, after i send a message to a specific person, there is an exclamation mark inside a little black bubble down on the lower right corner by the status info. 

What does that mean?
Does it look something like this? http://www.iqtan.com/_/rsrc/1349108748767/ios-6/9-iphone-messages/iphone-sending-and-receiving-messages/exclamation%20mark.png

This just means that the message wasn't sent, most likely because you are in an area with bad reception or Apple's iMessaging services are temporarily overwhelmed.

If not, please post a picture so we can better identify this.