The Overview (default) tab
When you navigate to a community, the first tab you see is the Overview tab.
This may go by another name if you chose to rename it during community creation, or if you later returned to the community setup page and changed it.
The Follow / Stop Following link above the Activity stream gives users an easy way to choose to follow this community.
The Activity Stream behaves just like the versions for My Newsfeed and My Profile. It shows actions taken in this community as well as microblog updates and questions targeted at this community with the @ control.
The community members thumbnail web part defaults to showing ten members (ordered by activity) but can be adjusted to more or fewer. It also provides a link to the members page.