The company apologized for the inconvenience to users. It said Sunday it will set up an investigation team and map out measures to prevent any recurrence. Yahoo Mail account holders can check via the service’s website whether emails addressed to them have been lost, along with the addresses of the senders of the lost messages.
http://www.japantimes.co.jp/news/2015/0 ... e7-V-GLT5s
I would think it's more than an inconvenience.
Yahoo Japan said it estimates that about 60 percent of the lost messages were unsolicited emails that were supposed to be blocked by the spam filter.
Sounds like they are guessing and hoping it's true that it was mostly spam, but what about the estimated 40%?
