Net Q & A

What are web bugs and how can you guard against them?

A web bug is a reference to a graphic image that is inserted into an e-mail message written in the language used on web pages, HTML. When the e-mail message is opened, it seeks out the image on the web site the author specified. By giving the graphic a unique name that is associated with that message, the owner of that web site can tell when the graphic is accessed.

It takes a little work, but not an extraordinarily high level of technical skill, to implant a "web bug" in an e-mail message. If you don't want to take the time or effort to learn to create web bugs, businesses like the Korea-based Postel Services will handle the details for you.

Web bugs are problematic, especially because they have great potential for abuse in a commercial context:

[P]rivacy advocates contend that such practices open a new window of surveillance on a traditionally private sphere of communications. They compare it to having someone who leaves a message on your answering machine — a telemarketer, say, or your mother — alerted the moment you listen to it. More troubling, they say, is that the same technology can be used to match a recipient's e-mail address with previously anonymous records of the Web sites visited from that person's computer.

Software to Track E-Mail Raises Privacy Concerns, NY Times, November 22, 2000. (Free registration required). 

Privacy Foundation Web Bug Regulation Proposal

Word Can Phone Home -- Jeff Beard explains how MS Word can be used to spy on users of Word documents, through the use of "web bugs."

Jerry Lawson