Facebook reveals another measurement snag (this time it's on mobile)

Facebook has issued an update on how it calculates the “estimated reach” advertisers can expect when buying media on the social network with the latest update revealing a further measurement discrepancy with Like and Share buttons on mobile – the latest episode in an issue that has dogged its year. 
The social network is updating how it calculates the numbers that appear in its estimated reach tool by updating the methodology for sampling and extrapolating potential a