I went on vacation last month, a pleasant road trip up the Pacific coast to Washington state. I didn’t intend it to be an experiment in social media deprivation, but because I had only a dumb cell phone and the occasional borrowed computer, it turned into one.

What did I learn by taking a three-week break from social networks? Well, first, despite my digital savvy, I’m not a social media native. I can function reasonably well when not tweeting or blogging for several weeks.

Second, though, I discovered how much of my daily life is nonetheless built around social media. I didn’t come back thinking how great it was to take a break from Twitter. Rather, I came backing thinking that I really need to get a smart phone.

Despite its urgency, so far I’ve resisted this new need (sort of—I acquired an iPad 2 instead). But though I still count myself as one of Amy Gahran’s majority of cell phone owners who have stuck with dumb phones, our dominance is fading fast. Whether because our feature phones get more intelligent or we give in and switch to smart phones, more and more of us will become ubiquitously connected.

For society as a whole, mobile connectivity may not be entirely positive. On my road trip, I picked up a copy of William Powers‘s recent book, Hamlet’s Blackberry. In it, he argues that while virtual connectivity is good, an excess of it undermines real-world awareness and involvement. The following scene, he says, is an all-too-typical sight:

“Standing at a crosswalk in midtown Manhattan one day waiting for the light to change, I realized that the eight or ten other pedestrians standing around me were all staring into screens. Here they were in the heart of one of the greatest cities in the history of the civilization, surrounded by a rich array of sights, sounds, and faces, and they were running away from it all, blocking it out.”

Though I tend to think that Powers doth protest too much, the scene resonated with me a night or two later when my wife and I were out to dinner. As the young couple at the table next to us waited for their meal, we noticed, they passed the time not by chatting together, but by consulting their smart phones. I can only hope they were instant-messaging each other.

Whether we like it or not, mobile connectivity is the new imperative. If you don’t understand and adapt to it, you will lose your audience. Some of the implications are obvious: For one, your website needs to be optimized for mobile apps. Other implications are subtler: If your audience can find you instantly, wherever they are, they will expect you to find and respond to them just as quickly. American Airlines, are you listening?