This article lists possible reasons why a message sent to a group does not appear in the group's message section.

Yahoo! Groups posts messages to the web site almost as soon as they are received. If you don't see your message, please wait a few minutes and check again. Here are some other possible explanations:

• You’re not a member of the group, and your message was returned to you or ignored.
• Your group is moderated, and the moderator has not approved your message.
• Your group is restricted, and the moderator has not approved your subscription request.
• You sent an email from an email address other than the one you used to register, and your message was returned or ignored. (We do this to prevent spamming.)