TechCrunch noticed a Twitter spike in reports of problems with Yahoo Mail, and another company called Downrightnow also reported problems accessing the service over the last several hours. Several CNET employees reported that they could access their in-boxes, but mine is unavailable. Yahoo Messenger and Yahoo's home page appeared to be working fine.
Please let us know if you're having trouble in the comments below, and we'll update this post with more information as we go.
Yahoo Mail is the most widely used Web e-mail service in the world by a wide margin, with over 100 million unique users in July, according to ComScore. Gmail, Google's Web e-mail service, is growing fast as the third most-popular e-mail service behind Microsoft's Hotmail but has suffered a few high-profile outages this year.
For more, read Yahoo Mail outages plague some users from CNET News.