Who knew? Porn on the New York subway. But then again, wasn’t it inevitable?

The place: A crowded afternoon N train from Manhattan to Brooklyn. The culprit: a Sony PlayStation Portable held by a young man sitting and watching in solitude, yet surrounded by plenty other strap hangers trying to get home.

What exactly happened here?

The first thing that got me was the audacity of it. With his PSP packed with genuine XXX fodder, simply put, what he was watching was nothing short of hard core pornographic visual certainly not intended for public transportation.

The next thing I noticed, no one seemed to pay attention. Hence - at least for the duration of my ride - no one seemed to mind.

What about the woman next to him, seemingly asleep? Another nearby busied herself reading, of all things, scripture. There were plenty  of other men and woman immediately around us while others got on and off the train.

Now, I know New York subway commuters have long learned to mind their own business.

But the video that unfolded in front of all of us (the sound was muted) clearly lowered the bar on anyone’s standard of privacy; clearly was so out of the ordinary that for its mere ostentatiousness, I figured someone would have to bring it up.

Above and beyond my own discontent about the young man’s obvious lack of social skills, I quickly found myself rather intrigued by something else in this - the apparent disconnect between device and audience.

What used to be a consumer video experience “curbed” by the lack of technology’s reach, a TV set and a VCR simply didn’t lend itself to any practical use in full public view.

This kept anyone’s viewing choice a private matter. No matter how sexual, violent, or mundane the footage was, consumption and intent remained locked inside the home.

Fast forward, today’s “anytime anywhere” video consumption capabilities have changed the playing field. The new paradigm: Anyone’s personal video experience is super-portable, devoid of any particular time, place, and for that matter choice of companion viewers.

Think about it.

Sprint Nextel recently started delivering WiMAX-enabled wireless broadband service powerful enough to give you downlink speeds of 25 Mbps or more while driving down the highway.

Essentially an open pipe into and out of the World Wide Web, it’s going to be interesting to see what passing cars are watching in the back seats once content is no longer limited to wholesome satellite subscription services or Disney DVDs brought along for the kids.

And what about in-flight Web access, such as the service recently announced by American Airlines for select domestic trips?

No matter whether on a highway, on an airplane or inside a subway car in New York, what’s OK for the person to the left of you might be unacceptable to the one on the right.

Clearly, with the pervasive nature of digital content and enabling delivery devices, the meaning of “privacy” is undergoing change.

As to my personal opinion, I am in favor of self-regulating one’s public conduct. Anything beyond that might quickly collide with core principles such as net neutrality or freedom of speech.

Still, our old-world definition of privacy seems to be changing as more of our new world trends towards digital and portable at once.

It’ll be interesting to see how this pans out.