A friendly URL is a Web address that is easy to read and includes words that describe the content of the webpage. This type of URL can be "friendly" in two ways. 1) It can help visitors remember the Web address, and 2) it can help describe the page to search engines.
Friendly URLs that are short and easy to remember are considered "user-friendly URLs." These URLs help visitors remember web addresses, which means they can revisit pages by simply typing in the URL address bar. For example, a company may use the URL "www.[company].com/support/" for the support section of their website. This is much easier to remember than a long convoluted URL, like "www.[company].com/section/support/default.aspx?id=1&lang=en".
Since dynamic sites often load different content based on the variables in the URL (which are usually listed after the question mark), creating user-friendly URLs is not always easy. Therefore, many webmasters now use a strategy called "URL rewriting" to create simpler URLs. This method tells the Web server to load a different URL than the one in the address bar. Therefore, a simple Web address can point to a more complex URL with lots of variables. Since the URL is redirected at the server level, visitors only see the simple Web address.
Search Engine-Friendly URLs
While user-friendly URLs are helpful for visitors, most webmasters are more concerned with creating search engine-friendly URLs. These URLs include important keywords that describe the content of the page. Since most search engines include the Web address as part of the information that describes a page, placing keywords in the URL can help boost the ranking of the page. Therefore, this strategy has become a popular aspect of search engine optimization or SEO.
For example, a blog that includes tips for Windows 7 may have a URL like "blogger.blogger.com/2011/02/windows7.html". A search engine friendly version of this URL may be "blogger.blogger.com/2011/02/helpful-tips-for-using-windows-7.html". While this type of descriptive URL may help with search engine ranking, it is important not to create ridiculously long URLs just to describe the page. After all, search engines still focus primarily on the content of each page when indexing websites.