The idea and implementation is really simple. You use Smart Keywords to search in Firefox and other browsers that you use, but how do you keep all the searches you do in sync? What if you want to use keyword searches for the first time?
Then when you want to search on, say, Wikipedia, just click the Shortwave bookmarklet and type w Earth. This Wikipedia article will pop up. Want to search the Internet Movie Database? Click the bookmarklet and type imdb Top Gun.
Shaun added a lot of default searches (Google, Google Maps, Google Images, Amazon, Flickr, YouTube, whois). Even better, you can upload your own search file to a server of your own and customize your search terms. I added a Lifehacker search and some others to my Waves file.
The best part about Shortwave is you can use the same bookmarklet on any browser on any computer you use. You can have the same search terms on your work and home computers, and on your iPhone or iPod Touch (as a webclip).
I emailed Shaun last week with an idea for Shortwave – I hesitated to use his contact form on his site because I hate bugging people through email, but he had closed the comments for posts related to Shortwave. I had an idea to implement site searches with Shortwave, where you could perform a search within the site you are currently browsing on Google. Shaun got back to me, and quickly posted this update to Shortwave implementing the functionality. Now you can search gs Shortwave and find posts on ChrisMLindsey.com with the term Shortwave.
Hopefully you will find Shortwave useful. If you implement any custom searches in your own Wave file, share them in the comments!