Hardware Problem Behind Yahoo Mail Outage
 

According to this Yahoo blog post, hardware problems are behind the company's recent e-mail outages. The good news is that the normal flood of daily spam from Yahoo accounts is down this week as well. We are very sorry for recent difficulties with Yahoo Mail. Some of our users have not been able to access their mail since 10:27 PM PST on Monday night, due to a hardware problem in one of our mail data centers. The issue has been harder to fix than we originally expected. We have dozens of people working around the clock to bring it to a resolution. We believe our current efforts will restore our users' access to their inboxes by 3 pm PST today.

http://www.hardocp.com/news/2013/12/...o_mail_outage/