UPDATE: I was right, tonight Google announced Google Groups is now part of Google Apps for Domains!
This morning I noticed a change in the way emails sent to a group (formerly known as list) email address on google apps for domains appear. Below is an example of the bottom of the email headers on an email sent to one of my groups on nick.pro:
On the other hand here is the bottom of the email headers on an email sent to that same group today:
As you can see in these images, a few new list specific header lines have been added that make lists appear more like they were handled by more traditional mailing list software, rather then a simple email forwarder.
I've confirmed this change seems to have happened today as emails to groups as recently as yesterday do not have the additional headers, while emails to the same groups today have the additional headers, hop past the break to see a breakdown of the 4 new headers and what I think this change means:
