Back in October, Google announced some changes to AdSense performance reports to improve usability and make the reports more visually compelling. One of the changes involved the ability to view changes to an account in more detail with the "Show events" checkbox or a separate event report.
"Change events are automatically generated and are shown as small flags on your reporting graphs," explains AdSense product manager Matt Goodridge. "Those annotations help you keep track of the actions you’ve taken in your account, like adding a new ad unit or blocking an additional category, and help you determine the impact of your changes."
Based on user feedback, Google has made some further changes.
"In addition to these automatically generated events, you can now also manually add notes you want to keep track of," says Goodridge. "This will allow you to find out whether actions which aren’t directly related to your AdSense account, like a website redesign or an advertising campaign for your site, may have had an impact on your earnings. Every user can see all the notes which have been added to an account by other users and can add, edit, and delete their own customized notes."
Users can add personalized annotations by going to "Performance reports," and viewing the changes as an overlay or a separate event report. From there, click "Add note" and you're all set.