You must have seen them.
Web addresses like http://tinyurl.com/2gj2z3 which, when you click on them, take you to another web page.
URL stands for Uniform Resource Locator. It’s the posh technical term for a web address. Web addresses normally take the form http://www.somesite.com/somepage.html, which is not too much of a problem.
But some site names can get very long, and so can page names. The increased use of database-driven sites mean that URLs can get very long indeed, and most of them is computer gobbledygook.
They are impossible to type in, if you are reading them in a print article, and often get corrupted by word-wrapping when they appear in an email or blog posting.
An URL shortener is a web service that takes a long address that’s hard to type, and turns it into a short one.
You should use them in articles for print publication, classified ads, emails, blog and forum postings, anywhere there is a danger that the full address may be corrupted, or that someone may need to type the address into a browser manually.