Google Web Accelerator, which was released in beta, is set up to automatically work with Firefox and Internet Explorer once it's been downloaded. The service stores copies of sites frequently accessed by individual PCs and automatically retrieves new data from those pages, so that a Web browser needs to process only updates to those sites when asked to load them. It can also automatically "pre-fetch" frequently used Web sites before the user downloads it.
However, users are concerned that the service can cache more data from their computers than they would prefer.
On a Google Labs discussion group, one user said that the security implications of Google caching details of Internet sessions were unacceptable.
"I went to the Futuremark forums and noticed that I'm logged in as someone I don't know. Great, I've used Google's Web Accelerator for a couple of hours, visited lots of sites where I'm logged in. Now I wonder how many people used my cache. I understand it's a beta, sure, but something like that is totally unacceptable."
Google was not immediately available for comment, but said in a Web site statement that the service can receive information such as the user's IP address, computer and connection information, and "personally identifiable information", such as an e-mail address.
"Whenever your computer sends cookies with browsing or prefetching page requests for unencrypted sites, we temporarily cache these cookies in order to improve performance," the company wrote on its Web site.
Information entered in SSL connections, such as Internet banking, will not be cached, the company wrote.
The service is only available to broadband subscribers.
ZDNet UK's Dan Ilett reported from London. For more coverage from ZDNet UK, click here.
