The latest issue with Yahoo was a breach that affected over 1 BILLON users. You can read about it here: http://www.cnbc.com/2016/12/14/yahoo-says-new-hack-affected-1-billion-users-separate-from-earlier-attack.html This came after another breach back in September, 2016 that affected 500 million users. Any provider that stores your messages encrypted will help counter this type of threat. See my other comment here for other providers to consider.