Google launched an upgrade to desktop search/Sidebar. There were a number of feature enhancements (remote PC/file access, "undocking" of plugp-ins and sharing functionality). That’s a very "quick and dirty" summary. The most interesting feature of the new enhancements from my point of view is the "social" or sharing dimension.
Users can send articles and "Web Clips" to one another via e-mail or IM or directly to each other’s Sidebars. And there’s some "wiki-like" functionality in that, in a few cases, people can be in the same module at the same time (think shared "to-do list"’). Right now that wiki/collaborative element is very limited, but it will likely evolve quickly as developers build more of these modules (which have become much more like Yahoo!’s widgets in this version).
Yahoo! has made huge bets on "social search" and other community functionality and Google has to date not done much in this realm. But the company is moving into tagging rapidly (e.g., Google Base) and these new "social" features of Sidebar create a community/viral dimension that Google hopes will boost adoption.
It’s also interesting to start seeing many elements coming together with intersecting or overlapping functionality: the personalized home page, personal search history, the upgraded toolbar, Gmail + IM, Google Talk in Sidebar, etc.
You can start to see some set of these functions closing in on some sort of "center," although there won’t ever be a single application I don’t believe. But over time Google will get a sense of where the concentration of its users are and what they’re doing and will emphasize those tools and applications accordingly.
Here’s the official Desktop Google Blog statement.