Ghostery and the Yahoo toolbar are extensions.<br /> https://support.mozilla.com/en-US/kb/Uninstalling%20add-ons#w_how-to-uninstall-extensions-and-themes Google analytics is a service for webmasters which collects statistics about usage of their websites. Not sure how that would affect website users - unless you installed a GA extension. If you got it, it can be uninstalled just like the other two extensions.

See also: * http://kb.mozillazine.org/Uninstalling_add-ons * http://kb.mozillazine.org/Uninstalling_toolbars