I use a lot of bookmarklets to make my browsing faster and more convenient. I use them to stop blinking text, subscribe to RSS feeds, post to this blog, hide all images on a page, and so on. One of the most important bookmarklets I add to my browser is one I found at MacWorld that enables you to search for text throughout the site you're currently viewing, not just the current page.
Just today, for example, I wanted to know whether I had ever blogged on the topic of boredom. So I navigated to the blog and clicked on the Google Site Search bookmarklet in my Links toolbar. In the dialog box that popped up, I entered "boredom|boring" and hit OK.
The bookmarklet piped my search text through Google's "site:" search filter and the browser returned a list of pages from my blog that contained the search terms.
I find the Google site: search to be more reliable than most web sites' built-in search facility. It's a fabulous addition to any Web user's research toolkit.