The decision was made by Judge Lucy Koh, who stated that all US residents who are not Yahoo Mail subscribers but who have sent emails to or received emails from a Yahoo Mail subscriber between October 2, 2011, and now may sue the company.
According to the class action, entitled Kevranian et al. v. Yahoo Inc., case number 5:13-cv-04547, in the U.S. District Court for the Northern District of California, Yahoo put in place a new email system which became the default interface for all Yahoo users in May 2011. At the time, Yahoo said the system could “look for keywords and links to further protect you from spam, surface photos and in time, serve users with Internet-based advertising,” the lawsuit states. After a short grace period, all Yahoo email users were switched to the new version.
Additionally Judge Koh stated that California residents who are not Yahoo Mail subscribers but who have sent emails to or received emails from a Yahoo Mail subscriber between October 2, 2012 and now may sue the company, according to the judge's filing in the U.S. district court in the northern district of California.
Koh made a distinction between this case and a similar class action filed against Google’s Gmail in 2014, in which she denied class action status because it was too determine which users agreed to Google's scanning practices.