Yahoo's Marissa Mayer on Mail outage: 'We really let you down'

"This has been a very frustrating week for our users and we are very sorry," wrote Mayer, on the company's official Tumblr blog. "Unfortunately, the outage was much more complex than it seemed at first, which is why it's taking us several days to resolve the compounding issues," she continued.

She concluded the post: "While our overall uptime is well above 99.9%, even accounting for this incident, we really let you down this week. We can, and we will, do better in the future."

While the e-mail outage itself was bad, the company has also been criticized for the way it handled its damage control. In her blog post, Mayer explained more of the details: The the outage affected 1 percent of the service's users, and that since the problem affected individual accounts in different ways, the resolution took longer than expected, she wrote. She also noted that some users were given a confusing "scheduled maintenance" message when they tried to access their inboxes.

The outage began Monday around 10:30 p.m. PT, and e-mail sent to the affected accounts were not delivered. The company also said on its help blog that messages delivered between November 25 and December 9 may not have shown up in inboxes either, though it was not clear if the reason was due to the recent outage.

Mayer said it was a "frustrating week" for Mail users, but it was no doubt a frustrating week for the company itself. Just to pile onto Yahoo's service woes, Flickr also experienced a minor outage on Thursday.