Reading/Search Engine Optimization

Background
The number of users and visits to Wikipedia are directly related to our global impact, pool of potential editors, and fundraising. The majority of Wikipedia users and visits come to us through Google search results - determined by a constantly changing algorithm and presentation scheme. This brings more people to our projects - readers, editors, donors.

Despite our current high rankings, we still have space in which to grow. Our high-quality results on English Wikipedia may not transfer to smaller projects. This creates an inequality of content access. We are also not investing in the most optimal ways to structure our content and potentially missing opportunities for improvement.

Research and implementation
Over the 2018-2019 fiscal year, we invested in the following:

Identifying weaknesses and opportunities for improvement:

 * Contracting GoFish digital to review and recommend improvements
 * Compiling and prioritizing SEO improvement recommendations
 * Researching the viability and effects of suggested improvements

Moving towards rigorous analysis:

 * Looking at current patterns in search engine optimization
 * Measuring effects of our changes through intervention analysis and A/B tests
 * Prioritizing for impact, starting with English Wikipedia before moving to other languages

Implementing changes to make sites easier to crawl:

 * Creating sitemaps to tell crawlers how pages relate to one another
 * Adding annotations that make our sites easier to understand by crawlers

Enabling Schema.org article linked data for main namespace pages
We began exploring schema.org markup within our articles as a means of providing search engines with more confidence within the context of ambiguous queries as well as with the general goal of increasing the amount of structure data across our sites overall. We began by adding the sameAs meta property to Wikipedia articles which pointed to the corresponding Wikidata entity. To determine the success of the changes, we ran an A/B test on 50% of articles across most of our projects (T206868).

A/B test results
Using hierarchical regression modeling of search engine-referred daily traffic to 269 editions of Wikipedia, we estimated the effect of adding the sameAs property to be a 1.4% increase (95% CI: 0.7-2.1) in average page views per day. Based on this increase, we decided to roll out the feature to 100% of main namespace pages (where applicable) on all Wikipedias.

The full report of our A/B test is available here.

Deployment Timelines
The sameAs schema property will be added to 100% of main namespace pages in April, 2019