The new button, called "Not My Email," will roll out this week and will be found under the "Actions" tab in users' inboxes. The button will help users of recycled accounts train their inboxes to recognize which email is intended for them and which is not, eventually rejecting email before the user has read it.
Yahoo said it also plans to help to users who have lost their Yahoo account due to inactivity. These steps include outreach to users by phone and email and extending the grace period for inactive accounts.
[ Some Yahoo users got more than they bargained for. Read more: Yahoo Recycled Emails: Users Find Security Surprises. ]
In a statement to InformationWeek, a Yahoo spokesperson said that users of inactive accounts will be notified one month in advance via their Yahoo Mail account, alternate email address and SMS if their account is subject to being recycled. If they don't activate their account within the next 30 days by logging into any Yahoo property, the email account will be scrubbed and everything deleted.
"We will then bounce emails to it and after a period of time open it up for anyone to register for," the spokesperson said. "At that time, the earlier account owner could try to register for it -- but their content wouldn't be in there. Alternatively, if someone else registers the account, the earlier account owner could go to watchlist.yahoo.com and pay $1.99 to get put on the watchlist for that name and 4 others."
According to Dylan Casey, Yahoo's senior director of platforms, the company monitored systems for claims about mistaken deliveries and were able to identify the problem with some of the accounts. The email bounce method, he said, was insufficient for senders to see that the email was no longer valid. Casey maintained that the email problem has affected only a small number of Yahoo users.
Casey also said that Yahoo is continuing to look into its Require-Recipient-Valid-Since protocol, a header that senders add to emails to check the age of the account before delivering a message. The company said it is reaching out to businesses such as Amazon, eBay, PayPal and Walmart to target emails to current users instead of the former account holders.
Yahoo's initiative to free up dormant accounts began in mid-June when the company first announced its plan. Yahoo said it would alert users who had been inactive for at least 12 months and instruct them to login to their accounts if they wanted to keep them. Accounts that remained dormant would be recycled and up for grabs.
In July, Yahoo opened up a wish list where users could name their top five choices for a username. In August, Yahoo contacted them if one of their IDs was available and sent them instructions to claim it within 48 hours. Almost immediately, privacy advocates and security analysts criticized Yahoo's initiative.
A Yahoo user cited in InformationWeek's story reported that the emails he received would allow him to log into the former accountholder's Pandora and Facebook accounts. He also knew the user's name, address, phone number, the last four digits of the user's social security number and where the user's child goes to school.
The other Yahoo users reported similar experiences: They received email receipts from Nordstrom, timecards that detailed mileage reimbursements, airline confirmations and an apartment application confirmation.