A URL, short for Uniform Resource Locator, is like a telephone number in that it gives a unique way of locating any web page in the world.

For Web Developers (or for users to request of their site)

A “friendly” URL is an address that is human-readable, void of unnecessary technical information, most common if the page is dynamically generated.

  • “Unfriendly” : …ucla.edu/example.php?title=UCLA%20to%20Lead%20National%20Effort….&date=2006-07-12%2009%3A45%3A08
  • “Friendly” : …ucla.edu/2006/07/12/ucla-to-lead-national-effort/

In addition, a technique called “URL rewriting” can be used to create friendly URLs and improve search rankings. A good overview of what it is, why it can be useful and how to do it: http://coding.smashingmagazine.com/2011/11/02/introduction-to-url-rewriting/