PUBLIC MARKS with tags interface & "search engine"

Search is, in essence, a command-line interface for the web. Command-line interfaces are what came before the “graphical user interface” popularized by the Macintosh and Microsoft Windows, and they’re popular among the engineers who actually build the web. So it’s no surprise that the world’s first universal interface for the web was, after all, simply a box into which you type some text, and can even append operators like “site:cnn.com” or “filetype:pdf.”

At first glance, Quicksilver is a launcher. Command Window When opened, it will create a catalog of applications and some frequently used folders and documents. Activate it, and you can search for and open anything in its catalog instantly. The search is adaptive, so Quicksilver will recognize which items you are searching for based on previous experience. It also supports abbreviations, so you can type entire words, or just fragments of each. When not in use, Quicksilver vanishes, waiting for the next time you summon it.