Shortwave by Shaun Inman is one of the most powerful bookmarklets that I use. Clicking on Shortwave in your bookmark bar simply opens a JavaScript dialog box that asks for a command. For example entering:

g Shortwave

will load the current page with the Google search results for ‘shortwave.’ And entering the command:

ip

Will return your current IP address, but the most powerful/interesting thing about Shortwave, is the ability to define your own ‘waves.’ Shaun gives you a default set of these waves in this text file: http://shortwaveapp.com/waves.txt, but you can modify it, and upload it to a server somewhere, and use your own list of waves, rather than using his.

It’s really pretty genius, and extremely simple to configure and use. Give it a shot, and let me know how you use Shortwave in the comments.

Readability is one of the greatest bookmarklets I have ever came across.

Readability is a simple tool that makes reading on the Web more enjoyable by removing the clutter around what you’re reading.

So basically, you drag this little piece of JavaScript to your bookmarks bar, and when ever you come across a page with lots of text, you bang on that little button. Readability tries to find the main block of content in an article, hides everything else, then pretties up the text to a font & size you specify.

Great Idea, Great Execution