We try our best to ensure that the data we publish are accurate and complete before, during, and after they are published. However, we occasionally need to make changes to the data after we publish it to allow for corrections and other improvements. We will maintain this historical log so that we can continue to improve our product while being transparent.
From time to time, Google changes how it classifies incoming traffic. This may result in changes to our graphs that do not reflect any actual changes in traffic to our services.
September 2011. We corrected errors in our graphs which caused anomalies that were most visible between September 19-23, 2011.
March 2011. We fixed a bug that was causing spurious traffic spikes to appear toward the end of the day in a small number of graphs, especially graphs for Iran.