• What is an Internet Filter and why do I need one?
• What is the difference between a "White List" and "Black List" filter?
• What are the limitations of "White List" and "Black List" filters?
• What other filter technologies are there?
• I trust my ___ (kids, employees, - fill in the blank), they wouldn't visit such sites.
• Why bother with filters, they're not 100% effective anyway?
• How do I go about Choosing the right Filter for my Family?

• Submit your Own Question

What is an Internet Filter and why do I need one?
Internet filters, sometimes called "content filters", are the terms used for the various methods employed to limit, manage or "filter" the information (often in the form of pictures) allowed into a PC from the internet. The need for content filters is easy to understand once you consider there are an estimated 1/2 million sites containing "adult" material (the generally used euphamism for pornographic images), and they can accessed just as easily as any other website - by typing in a URL (Universal Resource Locator - the www. address) in the browser of an internet connected PC.

What is the difference between a "White List" and "Black List" filter
Filters are designed to either include sites a exclude sites.  The most commong type of filters work by finding sites that are objectionable (and so should be excluded) and add them to a list. This is called an exclusion list or black list.   Sites that should not be visited are added to the list.  Before a site is visited, the list is checked; if the requested site is not on the list, it is allowed to be displayed.  This is how products like the Filterpak work.

Alternately, a list can be generated that includes all (and only) the sites that you will allow to be visited. This is called an inclusive or white list.  Again, before a site is visited, the list is checked. This time if the site is on the list, it is allowed to be displayed; if it is not on the include list, the site can not be displayed. This is the type list used in Kidsnet

What are the limitations of "White List" and "Black List" filters?
Filters are not perfect - each type has it's own limitations:
Exclude (Black list) limitations:  The biggest problem with exclusion lists is that the sites must be found to be on the list to be excluded; if the site is not first found and added to the list, then objectionable sites will be available until the are added

Include (White list) limitations: This type of filter is far safer because it starts out with only sites that have been approved to begin with, so in theory, every site that is allowed to be displayed should be an approved one. The problem is that the internet is a dynamic place; and sites change.  If  a site gets on the include list and then changes it's content (it's rare, but it happens) then it is possible to have an undesirable site on the list until it is discovered and removed.  The other (lesser) problem is that since the include list does include all possible allowable sites, it is possible that a new site or other non-objectionable site has not been added to the list and so is unreachable until it is added. Typically adding a site is simply a matter of submitting the site to the list keeping and it is added withing a few hours or perhaps a day.

What other filter technologies are there?
While the method of implementing filters are diverse (i.e. through software, "inline", or via proxy) the filter technique itself tends to be one of either an exclusive or inclusive list. However there is a another technology currently in use that does not use any kind of list and therefore does not need to be updated. It uses a technique we'll call Heuristic Content Management. The Heuristic process seeks to discover previously unknown information. When this process is applied to content scanning the result is a filter without a list. It uses the very technologies "adult" site operators use to  rate high in search engine rankings, and to attract visitors; to identify such sites containing "adult" material.  This technology is used in filters such as CyberSentinel

I trust my ___ (kids, employees, - fill in the blank), they wouldn't visit such sites.
Perhaps, but things do happen that could accidently or innocently lead someone to a porn site - for example - receiving spam (spam is unsolicited email) with an innocuous subject with a  link to such sites; searching on some innocous terms (a search on "white house" on some search engines will turn up porn sites. The point is, without somekind of tool to keep them on the right track, it is highly probable that any internet surfer will eventually wander onto an "adult" site. Consider the following statistics:

• 60% of American children admit seeing "adult pictures" on the Internet in the last year.
  
• There were 27.5 million U.S. visitors to adult-oriented pornographic Web sites in January 2002
  
• The term "sex" is the term most searched for on the Internet, about 1 in every 300.
  
• $320 million will be spent by Americans visiting "adult sites" by 2005, according to Jupiter Media Metrix.

• There are an estimated 500,000 websites containing pornography
  
• The FISS4F FilterPak filters out hundreds of thousands of pornographic websites.
  
  

Why bother with filters, they're not 100% effective anyway?
If everyone used this type of  reasoning, then no one would lock their doors, banks would not use alarms or guards, seat belts and air bags would not be required in cars, and so on - because few things in life are 100% effective. It would be foolish to refuse to take basic preventive measures like locking doors because it is not 100% effective against theives. Perhaps not, but it stops a lot of casual, opportunistic theft; makes it more difficult for theives, and serves as a deterrrent to theft. In the same manner, wouldn't it be wise to stop casual, opportunitic viewing of  "adult" sites, make it difficult to pull up porn sites on your computer, and so have a deterrent mechanism on your PC? The goal is to make viewing such "adult" sites difficult, not impossible.  That is what filtering software can do for you. Not locking a bank door is tantamount to an invitation to a thief. Not making it difficult to view porn sites on your PC is an open door on your computer waiting for a bad influence to exploit it.