Greasemonkey
Greasemonkey is an add-on for the popular open-source Web browser Firefox. Greasemonkey allows you to customize Web sites using Javascript. You don’t need to be a programmer to use it, either. If you can install a program, then you can use Greasemonkey. One specific Greasemonkey script I like adds Twitter Search Results on Google when you do a Web search. Remember, these are user-generated scripts so use caution when you install them.