“There will be a moment when you can fill out a form or something and give us money,” said Evan Williams, co-founder and chief executive officer.

“We’re working on it right now,” Williams said at The Wall Street Journal’s D: All Things Digital conference.

Williams and Twitter co-founder Biz Stone mentioned possible revenue-generators, including a service that would authenticate the source of information. For example, Dunkin’ Donuts could pay to make sure that impostors don’t send messages under its name.

Still, after nearly one hour of questions from journalists Walt Mossberg and Kara Swisher and from the audience, the co-founders gave no clear picture of Twitter’s business model. Stone demurred when asked what would be the company’s key revenue driver in two years.

Williams said he wasn’t opposed to banner advertising but was unenthusiastic.

“I think it’s probably the least interesting thing we could do,” he said.

Williams said one of his top priorities was hiring more people to help grow the company but he didn’t give a headcount target. San Francisco-based Twitter has 43 employees, he said, double its count in January.

Twitter allows anyone to write about what they’re doing or what’s on their mind in messages sent through the Web or cell phones, also known as “tweets,” which are limited to 140 characters. The unconventional, free service has attracted millions of users.

The co-founders said they know the hype surrounding Twitter won’t last forever.

“If you pay attention to it too much, you can run yourself off the rails,” Stone said. He added, “Pretty soon, everybody’s going to hate us.”

The privately held company has been a subject of buyout speculation by a big technology company, but Williams said he believed Twitter would remain independent.

Twitter founders plan to charge users

The device, according to published reports, will be a kind of miniature tablet computer. Like the iPhone, it would be able to access the Internet over cell phone data networks, allowing users to surf the Web just about anywhere. And analysts expect that, like the iconic smart-phone, the retail price would be subsidized by wireless carriers.

Those rumors have heated up amid the growth of the netbook market. Recent reports suggest that Apple will announce at least two new devices, including an updated iPhone, at its June developer conference in San Francisco. It’s unclear whether Apple will also unveil the new, larger touch-screen device.

Netbooks are small, low-cost laptops that are the fastest-growing category of PCs. They’ve become popular replacements for standard notebooks for travelers and families looking for a second or third computer in the house.

Netbooks sell for about $500 retail, but wireless providers offer them for as little as $100 upfront. They market them like cell phones, selling them below cost and making up for it with a monthly subscription fee from consumers.

The middle-aged woman was seen charging at a security guard at the departure gate, before screaming “aieyyahhhhh,” at the top of her lungs in a rant that lasts about three minutes.

The woman, sprawled on the ground, was seen wailing. An elderly man traveling with her tried to pull her to her feet but she shouted in Cantonese: “I want to go, I want to go.”

Cathay Pacific said it had already closed the aircraft’s doors and had offloaded the woman’s baggage, and so was unable to allow her to board the flight to San Francisco.

“Don’t be so upset, don’t be so emotional,” a male Cathay Pacific staff member is heard saying on the video.

Cathay Pacific said the incident occurred earlier this month, and the video appeared to have been loaded onto YouTube late last week. By Monday, the “woman going insane after missing her flight video” had over 400,000 hits.

In 2006, another sensational outburst by a stressed-out Hong Kong man captured the imagination of many people in this fast-paced, money-obsessed, Asian financial capital.

The middle-aged man, who chastised and swore at a youngster in a six-minute-long diatribe aboard a double decker bus, was dubbed “Bus-Uncle” and a video of the incident received close to two million hits.

His quote “I have pressure, you have pressure” became a catch-phrase and sparked navel-gazing at the pressure that many over-worked Hong Kong citizens suffer.

As for the woman at the airport, Cathay Pacific said it put her and her two travel companions on a later flight to Los Angeles, at no extra cost.

Hong Kong woman’s airport hysterics an online hit