I forgot I am in a yahoo group too LOL.
And just tried to join a horse group and had to have my daughter help me figure out the capcha letters.
the yahoo site seems slow to load...for me anyway.

on the page I joined on there are these settings for email-


[Step 2. Message Delivery

Yahoo! Groups lets you choose how you stay in touch.
Individual Email
The option to choose if you want to get each group message and special notice individually and immediately, as it is posted.

Daily Digest
The option to choose if you want to see all messages but limit the amount of email you receive. We'll compile an email of up to 25 messages and send daily (special notices too!).

Special Notices - Receive only important email notices from the group moderator.

Web Only - Don't get notified of the latest happenings. Read messages only on the web.

Step 3. Message Preference

Select a display format for any email messages you may receive:
Fully Featured New & Improved! Traditional]

so maybe it is one of those settings that you need to change???

so as soon as I get a message from the group I can be of more help so we can figure it out.