User blog comment:Rappy 4187/Technical Update: March 10, 2015/@comment-1251315-20150312231408/@comment-126761-20150316175303

The group can be used for stats in a whole variety of ways. It would be very easy to simply look at a single account in the poweruser group (the same way anyone already can), but we're not really interested in that level of data.

We're discussing whether to make this a completely hidden group, or not. Could go either way :)