While I was away, an interesting thing happened in the world of productivity apps for Mac. Nicholas Jitkoff, the developer of Quicksilver , was hired by Google to develop something similar for the company and its ever-expanding suite of apps. (Ars Technica carries the full story.)

The result is a sleek little app called “Google Quick Search Box”.

It has nothing like the power and range of Quicksilver, but it does provide a way to launch applications quickly and to perform a few other time-saving tricks:

As the name suggests, QSB is focussed on finding things. It doesn’t have the flexibility that Quicksilver enjoys, but it is good at searching. Of course, as one might expect, it excels at searching your Gmail archives and Google Apps documents.

But it can also find a bookmark in Safari or Camino and launch it, find a song in iTunes and play it, find a contact and display the information or start a new email to that person, and so on. It can find a document and offers the option to do one of six things with it:

A few weeks ago, extra plugins for the app began to appear, written by users, that expand its power and reach.

Aaron Ecay has written plugins for Firefox bookmarks, and two more that allow the interface to execute shell scripts and Applescript.

Martin Kühl has written plugins that access Leopard’s Services, search inside your Smart Folders and gain access to your Dock items. He makes these available on the github social coding web site where they are listed down the left-hand side.

(UPDATE: Nathan Parry has written a plugin for delicious.com that allows you to search and manipulate your bookmarks and tags.)

With these plugins QSB gains something like the power of Quicksilver.

For example, using Martin’s Services plugin, you can find a document, “tab” into it and type the first few letters of a Service to apply it to that object.

Here I am quickly emailing a text document to a student using the plugin:

Google’s Quick Search Box is freeware and Leopard-only. Like all software that is still in development, and especially one that works together with third-party plugins, you will come across an occasional glitch.

The latest builds are available from its project page on code.google.com. There is also a Google Group that keeps you up to date with conversations between users and the development team, and with even better plugins that are sure to appear in short order.