==Background
The Page Previews feature will be deployed in staged rollouts, beginning with Stage 0: Italian, Russian, Greek, Catalan, Hebrew. The performance on each wikipedia will be measured and analyzed.
== AC
[] T157700 is resolved providing 90% roll out
[] Restbase is enabled on stage 0 wikis (T158221)
[] Determine and apply appropriate sampling rate (within proper eventlogging limits (0.01%?)) per wiki
[] Deploy feature to 90% of users on Stage 0: Italian, Russian, Greek, Catalan, Hebrew wikipedias
After the beta feature is graduated make sure:
[] Those logged in users who enabled the beta feature will still have the feature enabled.
[] 90% of logged out users will have the feature delivered to them.
[] Events are logged for all users (as a basis of comparison)
[] Popups schema is updated to include whether the feature is enabled (isEnabled)
[] Feature is not present under the beta feature list
[] Complete a testplan run with TSG.
== Open Questions
* ~~Should this be implemented by making the Page Previews codebase lazily-loadable?~~ No. Given that all of the interaction handling code and the instrumentation will be required, we (the Reading Web software engineers) consider delaying the initial preview too much of a penalty.
* ~~Should we test all Wikipedias or only a portion?~~ We'll test on all stage 0 Wikipedias.
---
The original wording of this task, which is as follows, is still relevant but approached the problem from a performance perspective:
> There are a handful of instances where the majority of the Popups code needn't be loaded but is:
>
> * When the user has enabled the beta feature but has since disabled it via the settings menu
> * When the user is entered into the A/B test but isn't assigned the enabled condition (see T132604)
> * When the user has the [NavPopups](https://en.wikipedia.org/wiki/Wikipedia:Tools/Navigation_popups) gadget enabled
>
>== AC
>
> Answers on the back of a postcard, sent to mobile-l/wikitech-l:
>
> [ ] Can we really defer the loading of the majority of the codebase?
> [ ] Would it be worth it, i.e. what the impact on UX, if any, be acceptable?
> [ ] If it wouldn't be worth it, are there any small improvements that we can make to improve the status quo?