We have this ability turned on, so members can mark Docs as Helpful or Not Helpful. I haven't seen much use thus far, but I just did a promotion to encourage members to use the options. I'll let you know how it goes! We have quite a bit of old content, so I'd love some help being notified of what needs updating.
I'd honestly like to use the "mark as outdated" but I don't want to give the full community permission to mark as official, which seems to come with that permission!