This was a big week for the mobile phone industry, at least the US one, because of CTIA, the industry's huge trade show. And the biggest story, according to the New York Times, was competition for Apple's iPhone, as touchscreens, Web browsers, and multimedia features appear on more and more cellphones – together! Like the iPhone, these are really becoming media players + mini-computers, as well as communications devices. These little devices are so fun to play and work with – of course for teens too, the earliest adopters (or wannabes) – but it's good to keep in mind that they're also very avid photo- and video-sharers, as well as texters on phones, and there are both upsides and downsides to all this phone-based socializing and media-sharing. Last year, I cited an M:Metrics study finding that 70% of 13-to-17-year-old cellphone users in Europe and the US are creating and sharing content on their phones, photo-sharing being the No. 1 activity. Italian teens lead the way as phone media producers, followed by teens in Spain and the UK (tied for 2nd), then France, Germany, and the US, respectively (see this item). But the US is catching up, and among the positives, we're seeing some negative trends (see "Staging fights for Web video-sharing" and "Naked photo-sharing trend").