Since a few email lists that I belong to have been hit by spam recently, I thought I’d post this tip here. To stop spam in your Google group, assuming you’re the manager or owner of the group:
Choose Group settings, then Access, then scroll down to:
“Message moderation >>
No moderation – messages are delivered directly”
and check the box next to:
That solves the problem, in my experience.
Make sure that you promptly approve any non-spam messages. Make other trusted members of the group into admins: that way, these tasks won’t be neglected, even if you’re away from your email for a few days.