Microsoft and Yahoo are set go public on their privacy policies after the controversy surrounding search giant Google's data-retention strategy.

Both companies, according to a report in The Financial Times, will update their privacy policies in a few weeks and publicly reveal how long they plan to hang on to user's Web search data.

The action was prompted by the work of a group called the Article 29 Working Party, which advises the European Union on privacy policy and has also been in discussions with Google, said the The Financial Times.

Google's proposed US$3.1 billion purchase of online ad firm DoubleClick is being scrutinised by the European Commission following complaints from consumer and privacy groups there and in the US that a merged company would give Google access to an unprecedented amount of online consumer data.

Several months ago, Google changed its data retention policies, saying it would anonymise the final eight bits of the IP address and cookie data after 18 to 24 months, unless legally required to retain it for longer. The information on specific searches will be retained indefinitely, but the partial anonymisation will make it much more difficult to tie the searches to specific individuals or computers.

So far, neither Yahoo nor Microsoft have publicly detailed their data retention policies. A Yahoo representative did not return e-mails seeking comment on Friday. A Microsoft spokeswoman had this to say: "We can't confirm that. Microsoft doesn't have any information to share at this time."