The Electronic Frontier Foundation (EFF) has recommended that users avoid enabling this "search across computers" feature contained in Google's new desktop search beta.

The privacy pressure group warned that the storage of PC files on Google servers makes users more vulnerable to subpoenas from the government or private litigants.

Yesterday, Google released a beta version of its PC and web search application. The company said that the new version expanded the functionality of the product's Sidebar feature, a panel that provides information from a variety of information sources.

In the beta, the Sidebar pane can be broken up into individual panels, which can in turn be placed in different parts of the screen, said Sundar Pichai, director of product management. The Sidebar panels give users access to e-mail, news, weather, photos, stocks, syndicated website feeds and other sources of information.

Another enhancement to the Sidebar is the ability to share content with other users by sending it direct to another person's Sidebar or via instant messaging, in both cases thanks to an integration with the Google Talk instant messaging service, so both users need to be logged into Google Talk. Content can also be shared via e-mail, by launching an e-mail interface from Sidebar. To share directly from one Sidebar to another, both users must have Google Desktop 3 beta installed. This isn't a requirement for sharing content via Google Talk or e-mail.

However, the EFF said that the new features were an attack on users' privacy. It pointed out that the government and private litigants only need a subpoena to obtain personal files stored on Google servers, whereas it needed a search warrant to get them if they are on a PC in a user's home or office. This is because the Electronic Communication Privacy Act of 1986 affords less privacy protection to data stored on online service provider servers than to data stored on a home or work PC, the EFF said.

The EFF encouraged Google to join it and other organizations that are asking the US Congress to strengthen the privacy protection of personal data stored on the servers of online service providers.

Google didn't immediately respond to a request for comment about the EFF's warning.