our contact at comScore just responded and apologized for the delay. They say they'll run an internal inquiry and come back to us with more information but for now:

as you point out two large issues that come immediately to mind (as you mentioned) are Wikimedia Foundation not being unified, and the huge shift that we are seeing both here in the US and Globally from PC to smartphones and tablets.

We knew that our reports being:

1. desktop only (they don't offer global Mobile reports)
2. not unified (we don't use beacons, because of privacy restrictions)

the quality of comScore UV figures will deteriorate with time. The only pending question is if there's any additional anomaly or data quality issue that would explain the summer 2015 drop.

The August numbers have just become available and WMF sites are at 317M, a bit higher that the 294M in July, but basically sustaining the low level after the earlier sharp drop (from 430M in May). Hard to imagine that the global shift to mobile phones develops that rapidly during two months and then halts the next month ;)

Indeed, no news yet from comScore, I'll report back as soon as I hear from them.

@Tbayer is setting up a meeting (probably in the week of October 12) to talk about future directions with comScore data (including Analytics, Readership, Comms, Research).

Recommendation shared with the C-level.

Currently with Legal to review any existing agreement.

Closing this as we removed comScore reports.