THE LATTE CLASS.(The Talk of the Town)(Starbucks Corp. coffe shops)

On the train up from Philadelphia the other day, Bryant Simon, a professor of history at Temple University, overheard two conversations about Starbucks. When he reached Penn Station, he made a pit stop at the Starbucks at Thirty-fifth Street and Seventh Avenue. Then he began walking toward Grand Central, to catch a Metro-North train uptown, and passed a group of kids on the street, also talking about Starbucks. ("I guess a lot of people like twelve-dollar coffee," one said.) He was headed for the corner of 125th Street and Lenox Avenue: the site of Harlem's only Starbucks.

Simon, who is forty-four, is writing a book--a cross between "Bowling Alone" and "Fast Food Nation," he hopes--about the world's largest, and seemingly unavoidable, coffee-shop chain, which he has called "the corner bar of the twenty-first century." Over the past year, he estimates that he's been to three hundred Starbucks outlets in six countries. He sits in Starbucks for at least twelve hours a week, observing. In the course of his research, Simon has detected the occasional regional variation--in Guadalajara, for example, the Starbucks offers valet parking. But a few basic and universal mores hold true: moms predominate in late morning, teens take over after 3 p.m., and strangers who are not moms or teens must never engage one another.

At the 125th Street Starbucks, Simon quickly noticed a couple of irregularities, such as the hoop earrings belonging to one barista ("She shouldn't be allowed to wear those") and the lack of any ambient music or CDs for purchase. (Simon has obtained a copy of the employees' manual, and is contemplating applying for a summer job.) The store was busy and cramped--too cramped, he thought--and lacked the usual niceties like upholstered furniture. The dinginess struck him as more than coincidence. "It's a classic American story," he said. "African-Americans get less of everything."

Simon and a guest each ordered regular coffees, size Grande. All the tables were occupied, so they waited by the milk dispensers until a man in overalls sitting near the window got up and, in apparent violation of Starbucksian etiquette, approached. "There's a chair right here, and a chair right there," the man said, pointing at a couple of empty seats about ten feet apart. "Come on, it's a community thing."

Maybe it was a corner bar, after all. Simon took a seat by an elderly woman and a younger one. "I don't actually ...