The free video sharing Web site YouTube (www.youtube.com) just celebrated its fifth birthday, and looking at where it has come from and where it is now can shed some interesting light on where video may be headed.

In prehistoric times, back in the early 1990s, government officials, telecommunications executives, and pundits were talking excitedly about the "information superhighway," which was projected to encompass among other things "video on demand" and where personal computers and television were supposed to converge.

One of the early attempts at this, and probably the best, was Broadcast.com, a Web site where, just as with YouTube today, you could watch snippets of TV shows and movies as well as original programming, along with offering or participating in such business services such as press conferences and training sessions.

But this was before broadband became popular, and video quality was poor. The service in 1999 was sold to Yahoo, which discontinued the video offerings.

YouTube was launched in 2005, and Google bought it a year later. Today YouTube is the third most popular site on the entire Web, behind only Google and Facebook, according to the Web analytics company Alexa.

YouTube has never been, and isn't today, all about positives.

Most YouTube videos aren't what you see on television or movie theaters. They're short clips, with most users limited to uploading videos that are 10 minutes or shorter. On the other hand, some broadcasting companies and film studios have agreements with YouTube to upload entire TV shows and movies, which aren't easy to find from YouTube's opening page but can be found at www.youtube.com/shows and www.youtube.com/movies.

YouTube has been criticized for allowing copyrighted content to be shown, and several companies are suing YouTube, most notably the media conglomerate Viacom. YouTube doesn't screen videos before they're posted, but it does respond to takedown notices from copyright holders.

It also has an automated system for removing audio from a video when it exhibits "audio fingerprints" indicating it's copyrighted. This is the reason you'll see some videos without audio.

Some have criticized YouTube for trying too hard to appease deep-pocketed copyright holders and not respecting the fair use aspect of copyright law that can permit the reuse of small parts of copyrighted content without the approval of copyright holders.

YouTube makes its money through advertising, including banner ads, which are easy to ignore or click out of, and "pre-roll" ads, which aren't so easy to ignore. The latter are much like TV commercials, and they precede the video clip. Some people mute their computer's audio or switch to their email or another program until the ad is over.

YouTube gives some content creators a share in the ad revenue generated from their videos. These are typically large companies such as CBS, NBC, Fox, and BBC. But ordinary consumers can also work out such partnership agreements with YouTube, which will look at the video's content, the number of views, and if it includes unlicensed content. Credible reports have some people earning five figures for a single video, though this no doubt by far is the exception.

Anybody can upload their own videos, so long as you register, which is free. Anybody can watch any videos, even without registering, though registering gives you access to many YouTube features, including rating and leaving comments about specific videos.

YouTube has also been criticized for its lax parental controls. By simply lying about their age, teens and pre-teens can view suggestive material that borders on soft-core porn. The only solution, short of blocking access to YouTube completely through Internet security software, is to talk with children about what's appropriate and what can be harmful.

The next frontier for YouTube and similar video sharing sites is making it easier to watch videos on TV. It's simply more relaxing, particularly with longer videos, to sit back and stretch out than hunch over a PC screen. YouTube is introducing technologies to move in that direction.

Like much about the Internet, YouTube represents a great democratization. Anybody can create as well as consume. But there are negatives to this as well, including excruciatingly boring video blogs in which amateur videographers believe millions of people want to see their largely vacant talking heads commenting about news events rather than seeing video of the events themselves.

On the other hand, remarkably creative amateur works exist as well. Not to mention all the clips of hoaxes and practical jokes, politicians' goof-ups, and such historical footage as Neil A. Armstrong walking on the Moon.