A few hours after Microsoft took out ads playing off fears over Google's new privacy policies, the Web giant responded with a blog post noting that Microsoft has a similar policy regarding sharing customer data.

Betsy Masiello, a Google policy manager, took to the company's public policy blog to rebut "myths" that she says are being falsely spread in the wake of the Google's recent changes in its privacy policies that allow the company to share user information across different services. And she specifically singled out Microsoft for stoking those fears, noting that its privacy policies state that "information collected through one Microsoft service may be combined with information obtained through other Microsoft services."

Masiello also pointed out that Google offers users tools to manage their privacy settings and retrieve data from its various services if they leave them, something, she says, Microsoft's products don't match.

"We've always believed the facts should inform our marketing--and that it's best to focus on our users rather than negative attacks on other companies," Masiello wrote.

In an e-mail exchange with ZDnet's Mary Jo Foley, Microsoft's top spokesman Frank X. Shaw noted that "there is a difference between policy and practice." Microsoft, he went on to say, doesn't read customers' e-mail, for example, though Google's reading of that mail is done by a computer, not a person, in order to target ads.

The tit-for-tat is nothing new to the two tech industry behemoths. Last summer, the companies sparred in blog posts and tweets about who said what to whom in a patent dispute.

The fact that Masiello needs to respond to Microsoft and the concerns about Google's privacy policy change suggest yet again how the company has botched the way it's rolled out the revisions. Masiello notes that even though Google has changed the privacy policy, it hasn't changed the privacy controls that users edit and delete their search history or their YouTube viewing history, for example. She also points out that the new policy doesn't alter contractual agreements with big customers, which "have always superseded Google's Privacy Policy."