The move occurred less than a week after the Mountain View, Calif., search giant launched the test.
"We have currently reached our maximum capacity of users and are actively working to increase the number of users we can support," Google said Thursday in a posting on its website.
Web Accelerator, which was available at no charge, runs alongside a browser and directs all searches and page requests through Google's servers. To improve performance of broadband connections only, the application makes use of a cache, or data store, on the local computer, as well as caches on Google's servers, to store frequently accessed web pages.
But Google's Web Accelerator is a waste of time, not a time saver, for the group it's being targeted at, a research firm said Wednesday.
"Google's Web Accelerator will help speed searches via dial-up, but it is unnecessary for broadband users," wrote Gartner analyst Allen Weiner in an online research brief.
"Web accelerators were hot topics years ago, when many users were surfing the Web via dial-up connections. Today, with the popularity of broadband, an increasing number of users will not find a Web accelerator compelling," Weiner continued.
Google pitched its Web Accelerator to broadband users when it rolled out the free plug a week ago. Then, Google estimated that users could trim 2 to 3 hours from their online time if they surfed 20 to 30 hours a month.
Nor did Weiner see Google's Web Accelerator as something other large Web properties, such as MSN and Yahoo, would emulate. In fact, because "[Accelerator] cannot speed downloading of rich media files, such as large, network-clogging music and video files," Weiner noted that the caching techniques that Google uses will be made obsolete by the closed peer-to-peer networks based on instant messaging that AOL, MSN, and Yahoo are building.
These P2P networks promise fast file transfer, something that Google Web Accelerator can't.
Web Accelerator has come under criticism from privacy advocates for caching users' pages on its servers; there have also been scattered reports of some users accessing others' pages. Google spokespeople have denied that the download halt was due to any security or privacy concerns.
Under Google's privacy policies, the company does not track an individual's web activity, but does collect aggregated data from people using its services. The company has said that data collected from Web Accelerator won't be used in Google's advertising services for now. The company, however, could decide to use it later.