Apparently Google is trying to get out in front of this information as much as they can and have added a Google+ Help Center to the service. You simply go to the gear icon in the upper right corner of your Plus page and you will be taken here.
Mashable describes the effort as follows:
The “What’s new in Google+” section is essentially a list of release notes for the Google+ Project. The updates are smaller than Google’s traditional blog posts, but longer than most of its Help Center pages. It’s a centralized location for finding out what new features Google has added to its social network.
As Google is prone to these days they have included plenty of videos to help users get a better understanding of the service. Here is an introduction from the community manager for Google+, Natalie Villalobos.
If Google wants this “project” to succeed they will need to continue to differentiate themselves from Facebook with regard to transparency and ease of use. While this technique seems fine in the early stage with so many early adopters being very tech savvy, it will be critical that a full public launch to those with less understanding will be as dirt simple as possible.
Honestly, I am not sure that Google is capable of doing anything simply enough for the general population but they have surprised folks in many ways as of late so maybe they have some more up their sleeves?