Summary and Motivation

The <amp-sidebar> feature in stories has not achieved scale, but is creating an inconsistent user experience. It has also been brought up that the feature is an anomaly, as it's not one that's generally supported in story platforms. This has been demonstrated by the low adoption since launch, as compared to other features.

Alternative implementation suggestions for publishers

Rather than using links within a sidebar, publishers can look to these following suggestions:

1. Publishers can use <a> tags directly within their <amp-story-grid-layer> or <amp-story-cta-layer> tags
2. Publishers may load additional context in <amp-story-page-attachment>
3. Publishers can use <amp-story-player> to embed their story in another page, containing custom UI to present this data. See demo of this at https://codepen.io/mszylkowski/pen/dyOLKgE

Additional Context

We would like to start triggering warnings to inform publishers of the deprecation on a wider scale. After the warning period, we will deprecate the feature by removing its documentation and making its markup a no-op (to prevent invalidating documents).

In the future, we can file a separate I2R to invalidate the <amp-sidebar> markup within <amp-story> at a time where its impact is minimal. Before doing so, it may be a good idea to update the deprecation notice with a concrete removal date.