[Web4lib] the efficacy of filtering software

[Deborah Kaplan]

On Mon, 3 Jul 2006, John Fitzgibbon wrote:
> Because the Web is vast and ever changing it is not feasible to keep the
> black list up to date
> 
> Filtering software will fail to block a large number of pornographic
> sites.
> 
> Filtering software may, therefore, give parents a false sense of
> security; it may give them a mistaken belief that all pornographic sites
> are blocked.

For a colleague who needed to make a presentation to his local
public library's board, about six months ago I downloaded Net
Nanny and installed it using all of the defaults. I then spent 30
minutes looking around on the Internet and produced a report of:

1. All of the visual and textual porn I was able to find with no
problems at all, and

2. All of the legitimate and educational sites I attempted to
reach which Net Nanny blocked.

It was a frightening list. Now, obviously this was only one
software package and I didn't spend much time playing with the
defaults, but the general rules still apply.  Filtering software
gives a *very* false sense of security.  The only way to block
all porn is to have a whitelist of approved sites instead of a
blacklist of forbidden sites, and that can block valuable
information that your patrons need access to.

(As an entirely separate issue, note that filtering packages, by
default, filter what they want to filter and not necessarily what
you want to filter. While many of them are configurable nowadays,
configuring them still takes the time of a skilled individual.
Does your user community want to block only pornographic
photographs? Hate sites? Erotic text? Informative sexual text or
photographs (e.g. naked photographs for medical purposes)?
Mention of lifestyles it disapproves of? Most parents I've spoken
to assume that the filtering software has the same notion of
"offensive" and that they do, and so the false sense of security
is doubled in that they have no idea what is being blocked. If
you do install filtering software, you might want to think about
being very clear about what exactly you are filtering out.)

I'm happy to send that report (which is very informal -- an
e-mail to a colleague, not a formal report) to anyone who asks
for it.

Deborah Kaplan
-- 
Deborah Kaplan
Digital Initiatives Librarian
Brandeis University