We're aware of the problem with delayed messages affecting some messages
to some groups and are investigating the cause. Will update with more
information once we have it. Usually, once this type of problem is
diagnosed, it can be addressed quickly.

Apologies for the inconvenience. Please refer to the blog for the latest
updates:
http://www.ygroupsblog.com/blog/2009/04/23/message-delays/

- Yahoo! Groups Team