In that particular case, it is a print-formatted page that is designed to pop up that dialog automatically using a script. The regular article is at http://thebaffler.com/past/of_flying_cars (no /print on the end of the URL).

You can disable websites from displaying the print dialog and simply call it up yourself using the appropriate menu item or keyboard shortcut (or, with an add-on, the right-click context menu). One way to do this is to add a command to a file in your Firefox personal settings (Firefox profile) folder named user.js.

To open your currently active profile folder:

Help > Troubleshooting Information > "Show Folder" button

If you have a user.js file, open it, or if there is no user.js file, create one. Then add this line at the end:

user_pref("capability.policy.default.Window.print", "noAccess");

Save the file and restart Firefox, then test.

Alternately, you can create a default rule in the Controle de Scripts extension. An example is pictured. The issue with using this extension is that you need to be aware of its other settings, particularly related to pop-up windows.

Ah, duh. I didn't even notice the "/print" at the end of the url. I just followed a link from another website. Funny thing is, it was happening on other websites too, but I can't remember which were the other ones. Oh well.

Thanks for the help.