Groups want information about the group.
It increases their attachment to the group
You don't need to do all of the above. However, it's good to have a blog that outlines the latest community issues, your plans for the community, solicit opinions from members, highlight potential issues, recruit volunteers, and share the latest stats.
Not everyone will visit, perhaps just a few will, but these are the few that really care about the community.
You can now buy my first book, Buzzing Communities: How To Build Bigger, Better, and More Active Online Communities from the links below: