Can big email providers scan your messages in order to serve you relevant advertising? Google and Yahoo have long assumed the answer is yes, which is one of the reasons the giant companies provide free email to millions of people. Last week, however, a federal judge in California refused to throw out a class action case against Google, ruling that people who swapped messages with Gmail users — but do not use Gmail themselves — had never given the search giant permission to read their email. As a result, the judge ruled that Google could not simply say that the Wiretap Act did not apply, and permitted the case to go forwards towards a trial. Now, other class action lawyers have seized upon the ruling to file a new lawsuit against Yahoo on behalf of 100 million people who do not use Yahoo Mail but have communicated with someone who does.