If you've not come across Greasemonkey before and you're at all geeky you need to check it out. Greasemonkey is a Firefox browser add-on that allows you to use scripting in JavaScript to modify and manipulate the contents of Web pages.

Say, for example, you’d rather have a blue pinstripe background to the Google home page, Greasemonkey is how you’d do it. Your script would be triggered by loading the Google URL and would then traverse the page’s Domain Object Model (DOM) to find the body tag and re-write it specifying the URL of the desired background as the attribute of the background property.

Some of the scripts users have created and placed in the public domain are amazing. For example there’s LabelLinks4Gmail that works with Gmail and “allows you to label your labels as well as your e-mails, combining the best of both worlds.” A great idea.

This last script illustrates how complex interactions between Greasemonkey and Web pages can be. Here’s an even more interesting example: Memeorandum Colors.

Using an algorithm that scored every blog on the Memeorandum site according to how often and which political sites they link to, the creator of Memeorandum Colors built a Google Docs spreadsheet that indicates the blog author's political focus (that is, what the blog author is paying attention to not the blog author’s political persuasion).

Using a Greasemonkey script, Memeorandum Colors parses the page content when the user is on Memeorandum and colorizes it according to political bias (with color saturation showing the degree of bias) as calculated by the Google Docs spreadsheet.

Now exactly how useful Memeorandum Colors is as an intelligence tool in assessing the political tenor of the blogosphere I’m not sure but what is interesting is the concept of deriving metadata from one set of resources and then applying the result through another resource to illustrate bias or orientation.

This kind of off-the-cuff meta-analysis is going to become much more common as people find new ways to analyze and re-purpose everything from shopping recommendations to, as in this case, political commentary. This is a fertile playground for geeks, but for the naïve public it is going to be a minefield of half-truths, misinformation, and spin.

Mark Gibbs is a consultant, author, journalist, columnist and blogger.