Feature Description

Site Kit has many charts that display important information to our users, but it is hard to analyze how my site is doing since my last check a few days ago or after I publish a new post. I think it would be awesome if we can display these certain "milestones" on linear graphs such as "all traffic" widget on the dashboard page and audience overview on Search Console, AdSense, and Analytics module pages.

Here is a jsfiddle example of how to add vertical lines/annotations to linear charts: http://jsfiddle.net/NC37X/.

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Acceptance criteria

Implementation Brief

Test Coverage

Visual Regression Changes

QA Brief

Changelog entry