Charletta Johnson, 18, was wearing a T-shirt with the words, "Periodic Table of Texting" written above a chart of by-now familiar messaging abbreviations: OMG for "oh, my god," Thx for "thanks."
She was with her sister, De'juara Johnson, 14, taping up fliers for a church lunch event at San Joaquin Delta College.
Charletta said she got her first cell phone when she was 14, De'juara, when she was 12.
How important are those phones now?
"Very," the siblings said in unison.
"It's like our life," De'juara said.
"It's not just our life," Charletta said. "All our friends, everyone we know ... it's all on our phones."
Blacks and Latinos, who already own cell phones at higher rates than their white peers, also are more likely to use those phones to send e-mail and text messages, to take pictures, to get online, according to a report published earlier this month by the Pew Internet and American Life project, a national research center.
It's good news to those with worries about the so-called "digital divide," the gap - largely on lines of income and race - that separates those with access to technology and all its benefits from those without.
But it's good news with a caveat: While cell phones bring the internet to users who might not have it otherwise, its unclear whether the devices offer as robust an online experience as traditional computers.
At a MetroPCS store on Stockton's Hammer Lane, assistant manager Jennifer Rosas said customers lately are interested in phones that do more than make and take calls.
"It's all about Facebook, Twitter, that sort of thing," she said.
According to Pew, about 51 percent of Latinos and
46 percent of blacks - versus 33 percent of whites - use their cell phones to access the Internet.
Black (52 percent) and Latino (49 percent) cell phone users also are likelier than their white (26 percent) counterparts to store music on their phones, or to update profiles on social networking sites (19 percent for whites, 33 percent for blacks, 36 percent for Latinos).
Affordability could be one reason, said Lee Rainie, director of the Pew Internet and American Life project. A cell phone with a data plan is often cheaper than a home computer with Internet service.
But it's also true that minorities have been early adopters of cell phone media.
"One of the earliest addons to cell phones were ring tones," Rainie said. "And the hip-hop community, the African- American community, was extremely aggressive at promoting itself through those means."
Shonie Williams remembers using a clunky mobile phone in the late 1980s, and she said she's had a cell phone for most of the years since then.
"Forever, basically," she said.
She uses her phone for "Texting, picture messaging. Everything, you name it. Ringtones, downloads, whatever it'll do, whatever it's capable of doing is what I use it for."
Policymakers for decades have worried that communities without equal access to information technology would be left without critical skills and resources.
In that context, the news out of the Pew report is promising, if modestly so, Rainie said.
"Those who worry about the digital divide should take some level of encouragement from this," he said. "It brings a few more people to the Internet environment."
But, he said, "The thing that they worry about, though, is ... the experience of the internet on a handheld is less rich and potentially less meaningful than the experience you get on a big screen, connected to a computer."
So whether internet access through a phone helps students complete their homework or voters become better informed remains unresolved.
Nonetheless, that access is valuable, Williams said.
"How important is it?" she said. "On a scale of 1 to 10, I'd say a 10. It's my only way of staying connected. I would be lost without it."