I previously used a Google Group, to send an email to more than 102 people. This is now no longer working - my Google Group is not notified of a new post, automatically. Any idea what could have changed or be going wrong?Here, we see signs of the use of Google+ becoming more necessary.
Some months ago, Blogger, responding to a security vulnerability in BlogSend, changed the email address used by BlogSend. This required many owners of private blogs, using Google Groups to distribute BlogSend based email updates, to add "firstname.lastname@example.org" as a Group member. This requires the use of the Groups administrative control, to add a new member without consent.
The ability to add a new member, without consent (without requiring return confirmation from the new member), carried with it a warning, to Groups administrators.
If you misuse this option, your use of it may be revoked.This ability, when provided, was an excellent tool for spammers, to maintain a spam victim mailing list.
Recently, and possibly involving the misuse of "email@example.com" as Groups members, the option to add Groups members without consent was removed from the Groups "invite members" wizard. Now, any new Groups memberships require return consent from the new member.
This change leaves owners of private Groups unable to add "firstname.lastname@example.org" as a Group member - which leaves Groups unusable for distribution of private blog content. Private blog owners now have only one option - Use Google+, and properly restricted Circles, to selectively distribute blog post updates.
Note that owners of publicly accessible blogs can use Google+ also, in addition to the also popular option to use FeedBurner Email Distribution. Or, if you want to continue using Groups for distribution, set "Who can post messages?" to "Anyone can post", in the "Group settings" Access tab.