"You can think of it as a personal web assistant that learns about your habits and interests to identify and present web pages, news stories, and photos that it thinks you will be interested in," said Marissa Mayer, a director of consumer products at Google.
The "sidebar" appears on the side of a computer screen as a small vertical window that offers a series of "live" content panels and simpler ways to make notes and access e-mail, according to Mayer.
A "quick find" function enables people to search their computer hard drives or launch applications "as fast as they can type," Google claimed.
The software, titled "Google Desktop 2," was released in English with a promise it would be available in other languages "shortly."
Google's software release came in the throes of an online battle for market share with rival technology powerhouses Yahoo and Microsoft.