As of 8/21 5:30 pm PDT: The system failure that was causing message
delivery delays has been corrected. While our engineers have
identified and corrected the root cause of this issue on the Yahoo!
Groups side, you may still continue to receive messages from your ISP
over the next few days. We appreciate your patience as we worked
toward resolution and are sincerely sorry for any inconvenience this
has caused. We've taken measures to avoid a recurrence of this issue
in the future.

For more details on this issue, please visit the Groups team blog:
http://blog.360.yahoo.com/y_groups_team

Thank you,
Jami Heldt
Groups Community Manager