Processes data structure (usually a list) into a different order containing only those elements of the original data structure deemed as acceptable.  
 
API Method: uses operating-system programming interface that gathers information about a foreign application such as browsers and chat applications to seize control of a "foreign application" when the information gathered triggers a positive database of banned words.  Parental control using API technology shuts down the "offending application".

Proxy Server Method: ensures that a browser will communicate directly with the proxy server and the proxy server will then handle the request and take on the task of finding the web pages and returning them to the browser.  This ensures that the given workstation will always deal only with the proxy server rather than a foreign server, which also has the added advantage of speeding up the connection by catching content locally

ISP: Internet Service Provider

URL: Uniform Resource Locator

Tap or Span Port:  Hardware devices that provide a way to access data flowing through a computer network.
  
Choke point: (Borrowed from military terminology).  A carefully guarded channel between a local computer and the Internet through which an "attacker" would have to pass before arriving at its destination.  

Whitelist: A list of acceptable terms.  This list is inclusionary.  

Blacklist: A list of unacceptable terms.  This list is not inclusionary.  

Spying Programs:  Programs that seek to gather information that is private or confidential.