Members of the mobile phone industry had better start spending more time thinking about sex, according to the Yankee Group. Predicting a $192 million mobile porn industry by 2009, the group recently exhorted the mobile industry to act now to keep porn out of kids' handsets before regulators are pressured to act for them. “[It's] only a matter of time before parental outrage reaches the FCC,” the group said, so carriers should seek technological fig leafs, including child user profiles and wireless Web shutoff valves for parents.

Pornography has been a cash cow for every medium that embraces it (even when it involves embracing cows). But for the mobile industry, both the risks and rewards might be proportionally diminished because mobile phones represent perhaps the worst media imaginable for the consumption of pornography. The chief attribute of these devices is public portability, after all, which clashes with the typical, let's say, “user experience” of adult content. And those tiny screens might make porn visually indistinguishable from professional wrestling. It's no surprise that, while pornographers will fail to make $200 million off mobile phones in 2009, they'll continue to rake in billions annually from the wired Internet.

It's tough to say how successful the wired Internet industry has been at keeping prurient content away from young eyes, but considering how suddenly Paris Hilton became a household name among America's youth without having accomplished anything at all during daylight hours, it's probably safe to say there are still plenty of holes in the fence.

One uncomfortable topic still isn't being talked about, for obvious reasons: No matter what filtering software or user-profiling technique the industry develops, “adult content” can appear wherever there is visual communication between two people because anyone with a camera or video phone can instantly become a producer of “adult content.” This was true of PCs and Webcams, of course, but mobile cam activity will be more pervasive and easier to hide from parents. As a speaker at a recent telecom trade show joked, “I don't even want to know what my teenage kids would do with high-bandwidth video phones when they're in their rooms at night.” Likewise, most people seem to prefer avoiding the issue because it seems prima facie untreatable, at least at the industry level. Considering the aforementioned ill fit between mobile phones and the pornography industry, combined with the fact that even voice and text conversations can be pornographic, it seems the biggest threat posed by mobile phones to children's innocence might come less from some identifiable type of Web-based content and more from simply the person on the other end of the line.