Announced April Fool's Day Google's as yet unlaunched gMail service has attracted a hail of criticism from privacy advocates, concerned at invasion of user privacy.

On announcing the service, Google revealed plans for targeted advertising sales – based on a technology that scans emails in order to distribute appropriate ads with messages.

Last night, 28 privacy and civil liberties organizations – including the World Privacy Forum – called on Google to suspend its plans, partly because of that feature, and also asked the company to clarify its policies about data retention and data sharing among its business units.

They are concerned the technology will scan more intensively than virus filters. They are also concerned at the company's policy that lets it keep copies of user's incoming and outgoing messages – even after they stop using the service.

"The societal consequences of initiating a global infrastructure to continually monitor the communications of individuals are significant and far-reaching with immediate and long-term privacy implications," privacy campaigners warned, adding that the service may conflict with the EU Privacy Directive.

Google's creep-factor

Criticism is being levied at the manner in which mails from non-gMail users will be routinely scanned in order to deliver focused advertising, causing Center for Democracy and Technology associate director Ari Schwartz to say the service has "a definite creepiness factor." Some privacy advocates compare gMail to George Orwell's 'Big Brother'.

Answering its critics, Google VP engineering Wayne Rosing said: "Consumers can expect us to treat their email as private and with a great deal of respect. "I don't think we will are doing anything unreasonable," he told the Wisconsin State Standard.

Rosing stressed that a computer, not a human, will scan email content. Campaigners replied: "We think a computer system, with its greater storage, memory, and associative ability than a human’s, could be just as invasive as a human listening to the communications, if not more so." They have also initiated a complaint with the UK Information Commissioner.

Controversy continues for the not-yet launched service, with The Guardian this morning reporting that UK global market analysis firm The Market Age has been using the Gmail name since June 2002.

Market Age CEO Shane Smith said: "We must have the right to the name since we were the first to use it."