Dan Andreescu, 18/11/2015 22:32:
But that was explained to me as "we started filtering spiders better". So I don't think that would affect Alexa's numbers but maybe it's a bad coincidence that around the same time something else happened that dropped the numbers. And the convolution made us all miss it.
Or maybe the Alexa stats contained the same filtering error and fixed it at the same time as us! Sounds unlikely.
Nemo