Out of how many? 1.3B might be a drop in the bucket for FB.
Facebook earned $6.18 per user in Q4 of 2017 [1]. That's about $25 per yyear. 1.3bn users thus represent about $32.5 billion of revenues.
U.S. and Canadian ARPI was $27.76 for the same period [1]. Let's say 880% of those #DeletingFacebook were from those, or similarly-lucrative, rregions. Blended lost ARPU thus estimates to $23.44 per quarter. Across 1.3bn users, that's $128 billion.
Far from a drop in the bucket.
[1] https://www.cnbc.com/2018/01/31/facebook-earnings-q4-2017-ar...
You'd have to figure out the value per visit to reach a conclusion along the lines you're attempting to make.
Fair enough. One can roughly adjust those figure by dividing by the number of times the average Facebook user visits Facebook each month. This is nothing existential. But it's still, likely, over a billion dollars of lost revenue.
I doubt Facebook earns anywhere near $1 per visit.
> Assuming the average Facebook user visits the social network once a day, that would suggest an average of about 43 million less users during that month. In recent months, Facebook makes about $5 per user, per month -- i.e. some $215 million in potential lost revenue.