On my GS6 Edge with US Cellular, my conversation with one of my friends (also has USCC and GS6 edge) allows me to see when the message was read. In her conversation, the send button is green and the chat bubbles that I send are green (different from regular text messages). I first thought it might be from edge to edge, but it isn't like that with my friend who has VZW. THen I figured it might be from USCC to USCC, but my sister just got an edge and it doesn't do it with her. Is this a function I turned on somehow in her messages? I'd like to know some more about it...