You asked in this discussion thread and in comments on this blog post why recent groups activity was intermingled with Recent Discussions, Recent Documents and Recent Blog Posts on the home page. That was the functionality of our platform "out of the box". We heard your concerns about cluttering up the content feed, and our developers have fixed this problem. You will no longer see study group content in the recent activity boxes on the home page.
If you are a member of a study group and want to stay on top of the latest activity, just click on the Receive email notifications link on your group's home page. You will receive an email every time someone posts new content to your group. As always, we appreciate your feedback. It helps us make the site better.