"Wappalyzer shows you which software is used on the page you're currently at." You install it as an add-on to Firefox and then use it to determine whether the site uses Drupal, Wordpress, Joomla or other content management systems, or for that matter, other web tool libraries. Even if you are not techy, you may find it useful in evaluating what your next website should use.
https://addons.mozilla.org/en-US/firefox/addon/10229
If you use other browsers, you can also use wappalyzer as a bookmarklet.
The developer appreciates a $5 donation. Read more about him at http://elbertf.com/
