This is a real lifehack. I've been saving pretty much everything interesting in my del.icio.us account. Now with this hack I can search them with tags from the address bar of my Firefox. As a matter of fact, you can use this hack to search on any searchable field in any webpage.
1- Go to any searcahble field in a webpage. Say www.imdb.com
2- Right click on the field, and click Add a keyword for this search.
3- Add the keyword you want to use -imdb- and a name.
Basically what it does is it saves a bookmark to the search URL, with a %s placeholder for the search term, which is replaced with the actual search term when you type keyword searchterm in the address bar.
I love open source.