Thursday, January 7, 2010

Internet Filters and Email, Chats, and Attachments

(Fourth in a series of five articles on Internet Filters)

In spite of the problems of overblocking and underblocking, Internet Filters can be reasonably effective at preventing minors from accessing sexually explicit websites.  It is important to recognize, however, that computer users often do more than just surf the web.  Computer users also communicate with each other by a variety of means that are not as well controlled by filtering programs.  The most important of these are:

Email.  Users can exchange electronic mail messages with each other using a variety of programs.  Most email systems allow files to be attached to messages, including files that contain photographic images.

Instant Messaging (IM).  While email is asynchronous, meaning that the sender and receiver don’t have to be connected at the same time, IM (online chatting) takes place in real time: the sender and receiver have to be logged on at the same time.  Increasingly, the various programs that provide IM abilities allow file attachments, meaning that files containing photographic images can be transfer from one user to another this way.

File Transfer Services (Uploads and Downloads). There are websites that exist solely for the purpose of allowing a computer user to store one or more files online, with the option of keeping those files private or making them available to selected users or to any user.  Any user knowing the web address of an accessible file or list of accessible files can download (copy) the files to her or his own computer.

Different Internet Filtering programs handle these kinds of computer-based communications differently.  They’re all limited to the same kind of Black List, White List, and Text Pattern checking used to decide whether or not to allow access to basic websites, but the ad hoc nature of these other forms of communication makes the filter program less effective.  It is clear, then, that users can sometimes transfer pornographic images directly through the filtering programs without the program ever noticing a problem.  As long as there are no clues in plain text – in a message, in the name of the file being transferred, or in  text tags that might be embedded within the file -- the file will be passed through to the user.  Remember that without the clues in plain text the Filtering Program has no way of knowing what an image file might be about.

In a library setting there is often another – much larger – gap in what Internet Filters can control: the patron-owned computer.  Increasingly, public libraries provide free network connections, allowing library patrons to bring their own laptop computers from home to connect to the internet while at the library.  In some libraries, patrons can use an Ethernet cable to plug in to the network.  Increasingly, libraries provide wireless networking, allowing patron-owned computers to connect just be being inside the library building.  The gap, of course, is that there may be no filtering program at all on the patron-owned computer, so the patron can use her or his computer to access any internet materials whatsoever.

The point of all this is not to claim that Internet Filters don’t work.  Rather, the point is to inject some realism into a subject that is often treated with a great deal of wishful thinking and at times outright fantasy.  Internet Filters can be reasonably effective at preventing children from accessing sexually explicit materials available on websites.  They are significantly less effective at controlling communication that takes place by Email, Instant Messaging, or file transfers.  A patron-owned computer may have no Internet Filter installed at all, and can be used to display any internet content the user wishes to display.

Previous articles in this series:
            What are Internet Filters?

Future article in this series:
Internet Filters: The Constitutional Headache 

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