Helpful fans translated the argument from Cantonese and provided Chinese and English subtitles. Catchphrases such as "I have pressure. You have pressure. Why did you provoke me?" circulated throughout Hong Kong culture and were even printed on T-shirts. News agencies around the world ran stories about "Bus Uncle" and sent reporters to try and identify the man. Cultural commentators debated whether the video clip represented the emotional state of Hong Kong citizens and the pressures of living in such a densely populated society.

As of this writing, nearly four million people worldwide have watched the "Bus Uncle" video on YouTube. What began as a simple, weird altercation on a Hong Kong bus has turned into a worldwide phenomenon. And all because of a small company in an office above a pizza parlor in San Mateo, ­California.

Conceived at a San Francisco dinner party in early 2005 by former PayPal employees Chad Hurley and Steve Chen, ­YouTube was supposed to be a website that allowed people to post videos and share them with anyone. Some of the first videos ever posted were of Chen and his cat, PJ.

A beta version of the site debuted in May 2005, and the official site launched in December. Investors quickly seized the opportunity, and now, $11.5 million later, YouTube hums with nearly 60 employees. Each day, more than 60,000 new videos are added.

According to the information-services company Alexa, YouTube is the 13th most popular site on the Internet. In July 2006, 30 million people visited YouTube.

Placing a video on the site is easy. A user signs up for a membership and submits a clip, which is approved by YouTube staff and then added to the site. Viewers rate the clip, and software keeps track of the total viewings and rankings by day, month, and of all time. Clip length is limited to 10 minutes, but YouTube has recently added a Director program - designed for filmmakers, comedi­ans, and professional content producers - that doesn't impose a time limit.