I dunno.
Who are they texting? Who are they surfing the net with? It isn't all solipsism. How much of it is a function of the social network simply not being synchronous with the physical space they happen to be occupying?
A few years ago the college I teach at moved from 10 minutes between class periods to 15. As a result (since I often teach two classes back to back, by preference), I get to observe students inbetween classes a lot. And I've repeatedly been struck by how much more they were engaged with each other (despite the occasional cell phone ringing) than I remember being when I was a student.
Now, that could be because I was shy/anti-social/etc when I was a student, and so I'm projecting my memories on my classmates back in the day. But compared to where I was at 18-22, these students are socially very much engaged.
Also, part of it may be a consequnece of the multitasking people seem to live by now. When you try to converse with someone, you aren't just interrupting one thing that they already have their attention on; you're interrupting several at once.
I've always hated people asking me questions while I'm reading, at least if I'm fully engaged with the reading. But when I'm sitting at my desk in one of my rare productive moments, I'm balancing my attention between six firefox windows, many of them multi-tabbed, a couple text files, three or four mindmaps, and probably email on another screen. But I'm claustrophobic, so I always keep my door open; I can't retreat into a cave.
I need white noise or something. But when someone knocks on the door or stops at the table where I'm doing all this....I have to interrupt all that flow.
Not saying everyone texting/listening to the ipod is me. God forbid.
But I'm also not convinced they're all that anti-social/a-social/etc either. Its just that, of the 3000 or whatever messages they encounter every day, mine or yours just aren't going to be up on the priority list as high as we'd like.
And do not be conformed to this world, but be transformed by the renewing of your mind, that you may prove what is that good and acceptable and perfect will of God.
Romans 12:2 (NKJV)