"A confluence of events late this week, both internal as well as external, impacted our message delivery," Lisa Pollock, senior producer for Yahoo Mail, said in an email interview. "Some people sending to Yahoo Mail have intermittently had difficulty sending messages to Yahoo Mail users. We're currently making adjustments so that message delivery returns to normal, which should be very shortly."
Pollock also acknowledged complaints that "a number of users" were having trouble accessing their accounts Friday morning and promised a swift resolution to that problem as well.
In the case of the bounced incoming email, account holders were unaware that messages were not getting through to them.
"I've had this happen to my account without even realizing it since I was getting most of my mail," one Yahoo Mail account holder wrote in an email interview. "I had no idea I wasn't getting all my messages till a client called me and told me that their messages bounced."
Yahoo Mail normally returns incoming mail to senders when a destination account has exceeded its 6MB storage limit.
But in the cases in question, the service was accepting some messages while rejecting others without regard to the storage quota.
"Even with plenty of room, I have heard from three or so folks that their emails to me have bounced, which is somewhat disconcerting since it's my only email right now," said another Yahoo Mail account holder. "I've subsequently set up a Hotmail account as well just in case."
Free email services on the Web, which include Microsoft's Hotmail and offerings by every major portal site, have long been plagued by service problems. Yahoo today defended its position and ascribed some of its recent difficulties to capital improvements.
"We're one of the largest email systems in the world and continue to grow at an incredibly rapid pace," said Pollock. "We've recently been making architectural improvements to our system."