All the texting, e-mailing, and messaging used to bug me, but I've gotten used to it and even like it sometimes. I think it works best in a work setting, when you just want to ask someone one thing -- texting is relatively slow, and cell phone displays are so small that it encourages brevity. Another advantage is that you don't have to interrupt the person during dinner or whatever, so they can answer at their convenience. For example, I've found texting handy if I have a message for someone and it's dinner time or after 10 PM and I don't know if they're awake or not.
As for messaging, we do that to each other all the time at work too. It's great for talking about people behind their back

! It's also good for giving people account numbers, telephone numbers, IP addresses, etc. because you have a visual record of the conversation (so if they said something important you can save it on your to-do list), and you can copy and paste important information into another software program.
I do agree that I don't like it so much in a social setting though. One of my friends, who I'm sure has my cell # on one of her distribution lists, texted everyone to say Merry Christmas. How lame is that?
To quote Todd Bertuzzi though, "it is what it is." *shrug*