Like most applications, web browsers such as Netscape Navigator and Internet Explorer provide a fixed set of features. Users that want new features added must wait for the application developer to incorporate the features into future releases. There are however certain features that users can implement themselves by using filters. Since filters have the ability to modify web content, filters can actually implement new features by changing web pages before they are sent to the web browser. This section will discuss examples of useful features that are not available in most web browsers but can be implemented with filters.