I've noticed something about when people post to Social Group walls and then in the "Latest Group Msgs" column on the left of the page, you see the first few words of the post.
Normally nothing to be concerned about, but one thing that I've noticed can happen is that with groups that deal with personal issues, if the poster posts another member's name as the beginning of a wall post, that reveals that that person is a member of that group. Some people might not want that information revealed.
Obviously their membership in said group is public unless the group is structured differently, but it still might be advisable to begin wall posts in groups about sensitive topics with something other than the member's name. Just a thought.