2008 was the year that text messaging finally overtook voice calls. I talk about it all the time in presentations to clients. It wasn't just young folks, either... even people ages 35-44 were sending and receiving more texts than calls, and older folks weren't that far behind.
I have stories of friends who have abandoned the phone call. One of them generally won't answer if you call, and will only look at texts and return your call when he's not busy. Another told me that in the first month of his new relationship, he had not had a single phone conversation with the girl he was dating... they only texted.
Clive Thompson at Wired has a great article exploring "the death of the phone call." In it, he says the phone call is dying because:
"...everyone is in constant, lightweight contact in so many other ways: texting, chatting, and social-network messaging. And we don’t just have more options than we used to. We have better ones: These new forms of communication have exposed the fact that the voice call is badly designed. It deserves to die."
Great article, worth the read - Clive Thompson on the Death of the Phone Call.