When was the last time anyone bought a movie ticket from a human being?

Okay, that may be taking things to the extreme, but in recent years it’s become a fact of life for New York moviegoers: If we’re catching a blockbuster on opening night, then we should probably buy our tickets before even hopping on the subway. Today, in the lobbies of most Manhattan multiplexes, the longest lines are not those of people waiting to purchase tickets, but those of people waiting to pick up prepurchased tickets from computer kiosks.

Most weekends, the digital box office system works perfectly. But every once in a while, as a special event opens on only a select number of screens, or as a blockbuster crosses demographic divides and becomes a must-see for an entire cross section of the population, the experience of ordering an online movie ticket comes closer to the second-by-second Ticketmaster mania of buying a seat for a Radiohead concert. When “No Country for Old Men” arrived in theaters last fall, when “There Will Be Blood” made its debut last winter, and when “Iron Man” kicked off this year’s slew of summer hits, many moviegoers logged on around 3 or 4 on a Friday afternoon, only to find the majority of the city’s showings sold out.

Over the last month, this online rush has become even more pronounced. When “Sex and the City” exploded onto screens on May 30 on the way to a $57 million opening weekend, most pundits seemed stunned by the female-oriented runaway hit. But executives working at Fandango.com — the dominant online ticket seller for the theater chains located in New York City — knew the wave was coming. Less than 48 hours before the film opened, 10,000 moviegoers (almost all women) participated in Fandango’s “Sex and the City” survey, and not only were most of them planning on seeing the film during the first three days, but 67% said they planned to go to the film in a group, and 80% said they would be organizing get-togethers before or after the screening.

When all was said and done, 16% of the total opening-weekend ticket sales (roughly $9.1 million) were purchased through Fandango — a groundbreaking number for a wide-release feature film, and a figure that becomes even more dramatic when one realizes that Fandango does not service every major theater chain, and is not the only online operator selling tickets. (According to Nielsen/NetRatings, Fandango.com was visited by 6.3 million unique users in May, 60% more than its closest competitor, MovieTickets.com.)

“It was really a breakthrough moment, when you saw the way that viewers of various ages, in different cities, all rushed to save their spot in line by buying tickets online,” a Fandango spokesman, Harry Medved, said. “During the peak hours, we were selling seven tickets per second for ‘Sex and the City,’ and we’re finding that you can gauge a lot about what will be the weekend’s big hit, given the traffic we see. It was true with ‘The Simpsons Movie,’ already we’re seeing a lot of traffic on the ‘Mamma Mia!’ home page … and then there’s the excitement about ‘The Dark Knight,’ which opens on the same day.”

Last week, more than three weeks ahead of its opening night, there was an online rush by Batman fans to snatch up the IMAX tickets for “The Dark Knight” that had just gone on sale for midnight on July 18. Surveying his company’s sales last week, Mr. Medved said that despite the tickets being bought for last weekend’s two big hits, “Wall-E” (which opened to the tune of $62.5 million) and “Wanted” ($51.1 million), “The Dark Knight” accounted for 16% of its business last week. “You don’t want to read too much into it, but these numbers point to maybe the biggest film of the summer,” Mr. Medved said. “Many theaters are now planning 3 a.m. screenings to accommodate the overflow crowds … usually theaters would see this happening and would add a second or third or fourth screen for midnight, but when you have limitations, like IMAX screens, or ‘Sex and the City’ opening on fewer screens, things get sold out quickly.”

And it’s not happening just at the multiplex. At Film Forum, there has been an online scramble by art-house fans trying to get into the new Werner Herzog documentary, “Encounters at the End of the World.” “We keep a small percentage of tickets for the box office, but people seem to realize now that if it’s on the weekends, you have to show up pretty early — hours early — if you’re not going to buy your ticket online,” Film Forum’s Joe Berger said.

It’s not merely technological, this shift to digitally buying a ticket. It is an evolution that has reinforced Hollywood’s drive to create the big “event” movie, as well as the industry’s focus on opening-weekend box office.

And Fandango’s managing editor, Chuck Walton, said his company’s success has also had an impact on the communal nature of going to the movies.

“In 1999, I remember standing in line for hours at the Cineplex Odeon to see the new ‘Star Wars.’ It was a ritual to see who would show up the earliest to get the best seats,” he said. “Less than a decade later, it’s a whole new ritual. No one’s standing in line for days and weeks. Instead, the Facebook/MySpace generation watches the Internet like a hawk, and as soon as those ‘Dark Knight’ tickets are available in advance, shows are sold out within minutes. It’s no longer who can stand in line the longest, it’s all about who’s the savviest Web user.”

ssnyder@nysun.com