Cross-wiki Search Result Improvements/Design

This page documents and explores design ideas for cross-wiki search results. What are cross-wiki search results? They are search results from different projects, put onto the same results page. So for example, if you search for "pizza" on Wikipedia, you might see results from Wiktionary, Commons, Wikiquote, Wikinews etc. on the search results page. For general thoughts on this idea, please see Cross-wiki Search Result Improvements.

This is an open discussion and everyone is welcome to add their ideas, thoughts or designs on this page.

Existing Solutions
Several Wikipedias have taken the initiative and implemented interwiki search features on their SERP (search engine results page). These solutions often use Wikidata as a central source that contains links to other wikis.

Current cross-wiki search implementations
 * Cross-wiki search via https://it.wikipedia.org/wiki/MediaWiki:Search-interwiki-custom
 * Article placeholder results via https://www.mediawiki.org/wiki/Extension:ArticlePlaceholder
 * Wikidata info results via https://www.wikidata.org/wiki/User:Yair_rand/WikidataInfo.js
 * Sister project search links via https://en.wikipedia.org/wiki/Template:Sister_project_links

Separate versus Mixed Results
A fundamental question about displaying interwiki search results is whether they should be mixed in within Wikipedia search results, or displayed separately elsewhere on the page. Current implementations (mentioned above) all display interwiki results separately on the page (this could be intentional or just out of technical ease).

Tabbed interface

Sister wiki projects could be treated as separate "search verticals" that are divided by tabs, which is typical for many online search engines.

Intermixed

Mixed results brings search results from different wikis onto the same page, interlaced with search results from Wikipedia. The biggest challenge in presenting results like this is determining search relevancy across multiple projects for the same search term. These mixed search results should be easy to identify, visually, on the page.

A simple solution to make mixed results more identifiable would be to place an icon near each result, like the following:

Visually distinct cross-wiki search results
Make results from Wikiquote look like a quote and results from Wiktionary look like a definition?

Some search engines change how a search result is displayed, based on which search vertical it comes from. In our scenario, this would mean styling results differently, based on which wiki project they came from. The styling of the following distinct results draws from Wikipedia's own infobox feature, the hovercard, as well as from the mobile view - where smaller "bite-sized" pieces of information are highly prioritized: