URL shortening is meant for the purpose or can be said a technique through which any long web URL can be made shortened.
URL shortening makes link more manageable because long links are really very hard to remember. It is used for convenient messaging technology such as Twitter, which limits the number of characters that may be used in message. Twitter generally links a web-page in only 140 characters
URL shortening has been many times been criticized by many people because it has be utilized by spammer or of illicit internet activities.
Tinyurl.com is one of the oldest and my favorite URL shorten that has been linked by Twitter. This shortening service can be used without being signed up.
Here I have listed some top URL shortening services for your convenience: