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.

So what's there to watch? If you haven't checked it out yet, be prepared for the strangest, most obscure, clandestine, nostalgic, trendy, and pointless video clips ever recorded by the human race. In addition to the classic "Bus Uncle," you can find ­European music videos, Japanese anime, political news clips, soccer highlights, pet tricks, low-budget film parodies, amateur musicians, vacation videos, and an inordinate number of teenagers staring into a web camera and lip-synching a popular song. Adult-oriented clips are edited out; everything else is fair game. Links to these videos are spread via e-mail or are posted on blogs or other websites.

Media critics have attributed the ­YouTube phenomenon in part to our shortening attention span and to our access to technology, as well as to an increase in exhibitionism in our society. But it poses a problem for old-school media accustomed to spending money to produce videos and then recouping the investment by selling the content to viewers. Unlike cable or satellite television, YouTube is totally free.

In December 2005, a user posted a short Saturday Night Live film to the site. The rap parody was titled "Lazy Sunday" and depicted the very nongangster lives of two slackers eating cupcakes and going to see the movie The Chronicles of Narnia. Traditional film and television studios were stunned to see their copyrighted work passed around the world, much farther than the reach of Saturday Night Live itself. In one sense, it made the show relevant again to a younger audience. Unfortunately, all this exposure came without permission or payment.

Even though money couldn't buy such successful viral advertising, NBC issued a cease-and-desist order and demanded that all its clips be removed from YouTube. Another division of the corporation, the programming executives, wanted to know how they could get involved. NBC has since struck a partnership with YouTube to air the network's clips and previews on the website.