If Bill Gates ever had reason to doubt that the brash young billionaires of Google were out to get him, the time for such uncertainty is now officially over. Last month's dramatically revised version of its program Google Desktop is a glove slap across the face of Microsoft's fabled chief software architect. Obviously Google's update to a previous tool that searched people's hard drives in addition to the usual lightning-quick survey of the entire World Wide Web, Google Desktop 2 turns out to be a not-so-stealthy attempt to hijack the desktop from Microsoft. And in a move that must be particularly galling to Gates, the program does it in a way that directly steals thunder from Microsoft's upcoming Windows update, Vista. Specifically, I'm talking about Google's feature called Sidebar, a stack of small windows that sit on the side of the screen and dynamically draw on Web and personal information to track things like weather, stock prices, your e-mail, your photos, recently opened documents and Web destinations. Several years ago, demonstrating an early version of Vista, Microsoft proudly showed a column of on-screen 'tiles' that did the same kinds of things. Microsoft's name for this upcoming feature (which it still plans to include in Vista when it ships in late 2006): Sidebar. That's not all. Google product manager Nakhil Bhatla explains that another purpose of Desktop is to use the search box to quickly locate programs and files that you want to open—bypassing the Windows way of clicking on an icon or using the Start menu. Clearly, Google is squatting on Microsoft's turf, asking users to live in its environment as opposed to Bill's. Microsoft still believes that the central point of personal computing is productivity. That's why the desktop search in Vista will limit itself to probing the user's hard disk. Microsoft's explanation for this approach is that mixing Web-search results with hits from your own information is just too confusing. Things go more efficiently, the theory goes, when your personal data pond is segregated from the ocean of information data located elsewhere in the world. (Microsoft offers Web search as a separate program.) In contrast, Google Desktop searches bring results from everywhere—your hard disk, your email and billions of Web sites. That's because the Google mission is organizing and managing all the world's information. 'You shouldn't have to think about where the information comes from,' says Google VP Susan Wojcicki. Though Google-sites acknowledge difficulties in merging the personal with the public, their core belief is that the essence of 21st-century computing springs from the connectivity that allows all human knowledge, from books to instant messages, to be potentially shared. As Google tries to annex new information flows, it increasingly runs smack against issues of privacy, copyright and censorship. That's one part of Google's challenge. The other will be fending off Bill Gates, undoubtedly determined to prove that his vision of computing still dominates. From the first sentence we can infer that