Many of us use YouTube to send birthday greetings via the Internet or needed video footage of a cat treeing a bear or adopting birds. Yes, it has more serious purposes, but I digress.
The video sharing site, created in 2005 by three former PayPal employees, was bought by Google in 2006 for well over US$1 billion. Here is tech stuff about how it works.
YouTube’s success, as Wired notes, is in part related to how it was able to deal with the huge, perennial question of copyright:

Another major step was the way YouTube approached illegally uploaded material (see “It Plays Nice With Hollywood,” right). Instead of pulling down copyright-protected clips, the system lets studios and labels cash in on the ads sold against their content. Rights holders can earn a cut off videos they didn’t even upload.
Having been a permissions editor myself for many years, I do remember that persistent headache. No one could afford the rights to iconic characters in an exclusive jurisdiction. Children were even forbidden by teachers to make accurate drawings of Mickey Mouse. The only beneficiaries were copyright protection lawyers.
But what if the rightsholder has a financial incentive that users can afford? The Internet is hardly an exclusive jurisdiction.
Some say YouTube’s success was based in part on personal relationships: 

The YouTube story is not just about luck or timing but execution, and that’s part of the tale often ignored in their success. When we talk about founders we often like to hone in on their raw intellect but the ability to pull a team together is equally valuable and in the end, probably has more to do with success than any of their other talents. That’s why it doesn’t surprise me to see YouTubers sticking together at new startups such as Endorse and TheIceBreak. One gutcheck for entrepreneurs and leaders: would your former teams/colleagues work with you again? If the answer is “no,” then you are going to have a very hard time succeeding.
What I like about YouTube:
1. People often post science stories as vids, which is convenient for people who learn best by hearing/seeing, not reading.
2. I will never buy a greeting card for someone who lives far away again, as an appropriate vid will come on line.
What I don’t like about YouTube:
1. The irritating habit of checking up on my past searches, in order to suggest future ones, which is tiresome if one was only searching when developing a story. Maybe I never need to hear again about that sociopathic space alien from another galaxy, featured in a summer film. ;) 
Apart from that, YouTube is better than paying for private videography, if you have a message to get out. Note: We all use online information systems that we may or may not know much about. So every now and then I am going to devote a post to possibly useful background information on some of them,
Some of the information below will appear more useful than the rest:
 

Denyse O’Leary is a Canadian journalist, author, and blogger.