Google introduced a Sidebar panel in its online beta recently that personalizes desktop search with live information such as a real-time stock ticker, weather reports, news stories, and blog updates. It is self-learning, indexes past Internet use and is supposed to anticipate user preferences. In the process Google collects information on user behavior, reopening the confidentiality issue.

The so-called Google Desktop 2, a follow-on to the desktop search widgetry Google released last fall and borrowing from Apple's Dashboard and Yahoo's Konfabulator programs, can search network drives as well as local files and Outlook-based e-mail. The search index can be encrypted, but doing so impacts search performance.

Since third-party developers supposedly can use the Sidebar to concoct new value-added services, the widgetry reopens the door to speculation of a Google operating system. There's also a rudimentary test editor that raises the specter of a Google assault on Office on an ASP basis.

However, Sidebar stays on the desktop and so gives Google a high-profile piece of real estate and, if it gets popular, can present a serious challenge to Microsoft's browser and Microsoft as the conduit for most information.