For many publishers who have seen more success through mobile devices and apps than through their websites, website rankings can be a thorn in their side. At the same time, publishers who inflate their app engagement numbers have been happily unmonitored for a while now.That all may change. ComScore just announced the launch of its Media Metrix Multi-Platform, which will track visitors to websites, mobile sites and mobile apps, and then combine those tallies. The software is said to eradicate duplicate tallies and will give a truer sense of a publication’s audience and reach.This is great news for sites that excel on mobile, like ESPN and Pandora, which saw a huge rise in rankings when mobile audiences were included. But it can be a painful wake-up call for many publishers who have boasted about app “download” numbers but have not tracked how often those apps were used after being downloaded.The Media Metrix Multi-Platform is scheduled to be in Beta testing for the next several months, and initial reports are illustrative, not official, at this point.