According to a post by mxyzplk, mods can see "a dozen line graphs", from which the high-rep users can only see 3 and others can see none.
What are all those graphs (the 9 and the 3)? Why is this info only disclosed to the mods?
What are all those graphs (the 9 and the 3)?
25k users are granted access to an analytics tool in which they can see the overall number of posts and votes, and overall traffic, for the community as a whole (and not for any one user).
Diamond moderators get an analytics tool that is basically the same thing with more knobs and dials, and with additional kinds of stats. We can also see things like edits, closures, reopens, and some other things related to understanding overall site activity levels and moderation activities.
Given we're not allowed to share the specifics in public, I don't think I can say much more than that about what's in there exactly.
These analytics tools help us see big picture trends about how the community is operating. It's about understanding community health, like what's our close rate look like, how many questions get closed and reopened, etc. If we (the community, or just the diamonds) think there might be a problem in overall site activities then these analytics tools help us understand what's happening exactly.
Why is this info only disclosed to the mods?
I'm guessing it's because this is relatively secret information. Some users are given the 25k analytics because by that point they're fairly trustworthy as more or less acting as a good-faith member of the community. Diamond moderators are given a bit more because they've been verified by the electing community as being trustworthy. (& If this data leaks there's four people at most who could have been accountable for it, as opposed to a hundred.)