I still use it for friends & family because I feel I have to. They're all there.
One thing I think people should know, however, is what a closed group means. It means it's open for all to see who is participating. You can't read what the members say, but you can see who is on the membership list.
I mention this because once upon a time I started questioning my Mormon faith and joined a closed group (Mormon Stories) to ask questions. There were nice, knowledgeable people in there at the time but many members assumed it was anti-Mormon. To my surprise it generated quite a scandal for me at church because people could see I'd joined the group.
More seriously, I know of gay Mormon teens who at the time were coming to grips with their sexuality and joined a closed group. They didn't realize they would soon be outed to their parents and other church members via their membership being public.