Attorney Use of Free Email Services and Third Party Communications

Is the use of free email services like Gmail and Yahoo for client communications a violation of Rule 1.6(a) of the ABA Model Rules of Professional Conduct because  lawyers are revealing client information to a third party? Toby Brown says "yes" in Use Gmail - Waive Privilege? Check out his discussion of both email providers' TOS and the comments to his post on 3 Geeks and a Law Blog. See also Toby Brown's two follow-up posts: Gmail Waives Privilege - Part Deux and More on the Dangers of Freemail. [JH]