Editor's note: Amy Gahran writes about mobile tech for CNN.com. She is a San Francisco Bay Area writer and media consultant whose blog, Contentious.com, explores how people communicate in the online age.
(CNN) -- My "aha!" moment about the significance of cell phones happened in spring 2009 when I first moved to Oakland, California.
I was riding the bus. Sitting across from me was an elderly gentleman who looked homeless. A cell phone rang, and he reached into the pocket of his frayed jacket and pulled out a small flip phone.
"Hello? ...Yes, that's me. Thanks for calling me back," he began, apologizing for the noise of the bus. "Right. Yes, I just wanted to make sure my appointment was confirmed in your system. I did get that text message yesterday and I replied, but I just wanted to double-check that you got that and I made it onto your schedule. OK, good, good. Yes, I'll be there tomorrow. Because I'm really serious about getting off the streets this time."
While I was eavesdropping on this conversation, I had my iPhone out and I was checking Twitter. This may sound frivolous -- but on my screen at the very moment were two notable tweets: an announcement of a significant development on an energy policy topic of interest to me (but that receives scant media coverage) and an update from a friend I hadn't seen in years saying that her third chemo treatment for breast cancer had gone easier than the first two.
In seconds, I'd retweeted the policy update publicly to share it with my more than 5,000 Twitter followers; then I privately direct-messaged a note of support to my friend.
Then I put away my iPhone and paused to consider the guy on the bus. I didn't talk to him; I just took in his tattered clothes, the stuffed-to-bursting gym bag on his lap, his deeply lined and tired face.
This is how cell phones have changed our lives.
Yes, cell phones can be distracting, annoying, trivial and frustrating. Yes, they generally offer poorer quality, less reliable voice call connections compared to land lines. Yes, they can be an attention-absorbing cloak that people hide behind to isolate themselves from the people around them. ("Resist the urge to hang out with your cell phone," advises Tanya Davis in her poignant video poem How to Be Alone.)
But cell phones also now provide vital services and human connections. They connect people in dire need with services that can change (or save) their lives and offer new hope, even through simple broadcast text messages. In the same month as my eye-opening bus ride, a Washington Post story explained how cheap cell phones have become a lifeline for D.C.-area homeless people.
Cell phones allow us to quickly share important news that often doesn't make it into the daily paper or evening newscast. This is becoming even more true as so many established news brands are slowly imploding (mainly due to bad management decisions over the last 15 years -- not, as often is claimed, due to the advent of the internet and cell phones).
Cell phones allow us to extend the presence of internet-enabled communications into the spare moments of our lives, wherever we are, so we can reach out to our friends when we're on the bus or in line at the bank.
Cell phones also are making and shaping news, especially on the local level, where news coverage has been waning.
Several video-enabled cell phones were on the scene at the January 1, 2009, killing of Oscar Grant, a 22-year-old African-American resident of Oakland, California, who was returning with friends from New Year's Eve celebrations in San Francisco. Transit police officer Johannes Mehserle had Grant face-down on the cement station platform when he fatally shot Grant. Nearby, on an idling BART train, many bystanders watched. Several videoed the incident with their phones.
Some videos of this shooting were uploaded to YouTube within hours, sparking instant fury through a city where race-charged police violence has long been a flash point. The cell phone videos were also key pieces of evidence during Mehserle's trial. (On July 8 he was convicted of involuntary manslaughter and awaits sentencing.)
Looking back on the significance of cell phones in the Grant shooting, I reminded participants in last weekend's video workshop at the Society of Environmental Journalists conference that journalists need these skills, too. Whatever media skills and tools people in your community are using, journalists should be prepared to monitor and use those channels as well. Unfortunately, right now most journalists lack these skills -- but more are catching up.
The prominent role of cell phone media in the news of the Grant shooting also provided the inspiration for the community news and views site that Susan Mernit founded in 2009, Oakland Local. I co-founded this site, and am working to make Oakland Local more easily accessible via the inexpensive "feature phones" commonly relied upon by the majority of Oaklanders.
Yes, smartphones do matter. I own a smartphone, and I use it nearly constantly. (Over the summer I ditched my iPhone in favor of the Droid Incredible.) However, smartphones are not the biggest piece of the mobile landscape. You may not be able to tell this from tech news coverage, but most Americans still don't have smartphones.
Cell phones have become nearly ubiquitous in the United States, but judging by the kinds of phones most Americans use, smartphones are too pricey or complex for the majority of us. Although cheaper Android phones that bridge the gap between feature phones and smartphones are starting to hit the U.S. market, there will probably always be a noticeable mobile digital divide. Many people on both sides of that divide are learning how to make the most out of the phones they have.