What do the different colors mean in iMessage?

[Huey Newton]

What do the different colors mean in iMessage?

 

[Just_Me_D]

Blue represent iMessages / messages that can only be sent and received via members with compatible Apple devices. It also represents contacts who have iMessage enabled on their devices.

Green represents SMS/MMS message and well as contacts who do not have an Apple device or who have iMessage disabled.

 

[John Yester]

Yup Also blue is your messages and grey is their messages.