The following is a guest post from SendGrid Senior Deliverability Analyst, Tim Starr. Yahoo! recently announced that they will be recycling email addresses that have been unused by their owners for 12 months or more. They gave the account owners one last chance to reclaim those addresses by 7/15/2013. Unreclaimed addresses will hard-bounce for 30 days afterwards, then they will be eligible to be claimed by new users. This may result in a temporary increase in hard bounces from Yahoo! domains such as yahoo.*, ymail.com, and rocketmail.com. After that 30 day time period, any email sent to those addresses may end up going to their new owners instead of their old ones. What should you do about it? Make sure you’re getting all the bounces from Yahoo! addresses you send to between 7/15/2013 and 8/15/2013, and scrub them from your list so you don’t send to them again. It would also be a good idea to identify all Yahoo! addresses you have with no opens or clicks in the past 12 months, so you can either send them a reconfirmation email or stop sending to them entirely. If you have a site that people log into with any of these inactive Yahoo! email addresses, you may want to prompt them to update their email address the next time they login. For more information on this change, read Yahoo’s release here and for tips on how to ensure that you’re keeping your lists clean, download our free webcast: Highway to Hell: Top 7 Fastest Ways to Land in the Email Underworld.