- to share a page or an article on LinkedIn or Facebook;
- to translate a site to English or Dutch;
- to read a page with Readability;
- to save a bookmark on Diigo; or
- to shorten a URL using goo.gl.
But that's only my selection. You'll find more inspiration on Lifehacker.com, MakeUseOf.com, or in Lifehacker: The Guide to Working Smarter, Faster, and Better by Gina Trapani & Adam Pash.
Do you use bookmarklets?