TinyURL is a URL shortening service, a web service that provides short aliases for redirection of long URLs. Kevin Gilbertson, a web developer, launched the service in January 2002 so that he would be able to link directly to newsgroup postings that frequently had long and cumbersome addresses.
The TinyURL homepage includes a form that is used to submit a long URL for shortening. For each URL entered, the server adds a new alias in its hashed database and returns a short URL such as http://tinyurl.com/2unsh in the following page. If the URL has already been requested, TinyURL will return the existing alias rather than create a duplicate entry. The short URL forwards users to the long URL.
TinyURL offers an API that allows applications to automatically create short URLs. This is done by simply reading the result returned from tinyurl.com/api-create.php?url=SOURCE_URL.
Short URL aliases are seen as useful because they are easier to write down, remember or pass around, are less error-prone to write, and also fit where space is limited such as IRC channel topics, email signatures, microblogs, certain printed newspapers (such as the .net Magazine or even Nature), and email clients that impose line breaks on messages at a certain length. People posting on Twitter make extensive use of shortened URLs to keep their tweets within the service-imposed 140 character limit (Twitter had used TinyURL until 2009, then it switched to bit.ly; now Twitter uses its own t.co domain for this purpose).
Starting in 2008, TinyURL allows users to create custom, more meaningful aliases. This means that a user can create descriptive URLs rather than a randomly generated address. For example, http://tinyurl.com/wp-tinyurl.
The ability to preview the full URL is present at TinyURL. To expand the URL, manually add the subdomain “preview” before “tinyurl.com”. Instead of redirecting the browser to the site specified in the full URL, it first goes to the TinyURL site where the full URL is displayed. If the user is satisfied with the result, they can click on the hyperlink to continue to the destination. This feature is not well documented at the TinyURL site, but the alternative shortened URL with preview capability is offered as an option at the time of creation.