Keeping Firefox+Flash from eating your CPU

[Jonathan Ryshpan <jonrysh pacbell net>]

In a recent issue of Salon, I read:
        Luckily, there's a small add-on program for Firefox that lets
        the user prevent Flash files from running automatically when a
        page loads, and it turns Firefox into a stable, efficient
        browser.
This appeared in:
        http://www.salon.com/wires/ap/scitech/2008/09/02/D92V0RV01_tec_tech_test_google_chrome/index.html

Does anyone know what this application/applet/plugin is?  Is it
available for Linux?

Thanks - jon