If you are one of the many who feel that the media are unforgivably biased, the Web now has a solution for you. Greasemonkey, an add-on for the open-source Firefox browser, can act as a programmable content filter, sanitizing or scandalizing the news before you see it. For fun, we wrote a simple script (detailed below) that lets Greasemonkey rewrite the news ungrammatically, or render it politically incorrect or even offensive. No matter where you stand on the political spectrum, you'll see that Greasemonkey and related technologies are destroying one of the last one-way streets in the media world. While the Internet may be interactive, many of the most trusted and reputable websites still treat readers as passive recipients of content. Pages are rendered on the computer screen more or less the way the publishers intended, and your job is to consume, not to participate.

But of course, Web pages are nothing more than large collections of bits, and bits are easy to flip, cut, and splice. Nothing can stop the data that the New York Times or MSNBC sends to your computer from being modified before it is displayed.