Rodney, an artist/poet/landscaper who also happens to be my wife’s old boyfriend, got his mobile phone bill the other day and was shocked to see that Echo, his 16 year-old daughter, had the month before sent or received more than 14,000 SMS text messages from her mobile phone. Yes, Echo has unlimited texting, but among her friends this behavior isn’t unusual and it says a lot about how media habits — good and bad — are changing in our culture.

If a typical month has 30 days that’s 720 hours, a third of which we’ll guess Echo spends asleep, giving her 480 hours of texting time per month. Fourteen thousand texts (the number was actually higher, but we’ll round it down for simplicity) divided into 480 hours is about 29 texts per hour or about one every two minutes. Since texting is usually a binary activity (the texter sends a text for every text they receive) we can guess that Echo writes about 7,000 text messages per month, with writing probably taking twice as much time as reading. Half an hour at the mall with a stopwatch told me the average teenage SMS message takes about 20 seconds to type (if you can call it typing) suggesting that Echo is spending about a quarter of her waking time on texting.

According to both Neilsen and the Pew Internet Life Project, Echo is an outlier, a user of texting at prodigious levels beyond her peers. A Neilsen study from the second quarter of 2008, for example, says that mobile phone users age 13-17 send or receive an average of 1742 texts per month, which would only require 7.25 hours by my reckoning. So Echo is an outlier, but on the other hand her data is fresher and texting IS rising at a rapid pace.

So who cares? Advertisers care. Kids who are texting aren’t attending to TV ads while they are doing it, nor are they reading magazines or newspapers (what are those?). So advertising is coming quickly to SMS.

TV executives care. Remember those words “standard text messaging rates apply” at the end of every American Idol episode? Well for reality television, texting means revenue. Idol averages 30 million voters per week of which a quarter are using SMS that reportedly yields a nickel per vote to the TV producers. Seven and a half million messages per week and 12 weeks of voting yields another $4.5 million per season for Simon and the gang.

Educators care because texting competes with other activities like paying attention at school and doing homework. Keeping kids from texting in school is almost impossible.

To really understand the Echo phenomenon, though, you have to appreciate that she’s a very pretty girl living in a semi-rural area where kids like to complain that there isn’t anything to do. So they gossip. If teens twittered, which studies show they don’t, Echo would be a twitterer because her peers are interested in her life. And THAT’s what really makes her an outlier, because Echo is an opinion leader and a trend-setter and SMS — generally a one-to-one technology — isn’t well-suited for that. So the poor girl has to work really hard to keep all her friends informed, using an antiquated interpersonal communication technology as an ad hoc social network.

What’s most interesting to me about this phenomenon is the part about teens not twittering. All the studies show that’s true but don’t seem to look for causality. They miss the simple point that twittering is public behavior (one-way at that!) and texting is private and bi-directional. An adult or a teen celebrity might twitter but most regular kids see what they are communicating as too private to share with anyone other than the person for whom it is intended, much less any old creep who chooses to subscribe. And divas like Echo, who might happily embrace a more public channel, are trapped by the tools of their audience.

Girls age 13-17 are interested in relationships (who likes who) and boys age 13-17, who would normally be interested more in things, also happen to be generally obsessed with girls age 13-17, effectively dragging boys into the sway of SMS, too, sustaining an industry.

There’s clearly a new product opportunity in here, somewhere.

Andy Hertzfeld tells how Steve Jobs used to argue for a faster-booting Macintosh citing the man-years and lives it would save. But that’s nothing compared to the impact some twitter-like hybrid SMS product would have for a girl like Echo. It could change her life. Maybe even free up enough time for her to get into Duke.

And as the central node in an Idol-like SMS network, her popularity might even cover some of that Duke tuition, too.