The search engine Yandex has updated its ranking algorithm to give mobile-friendly websites a higher SERP position when users are searching from a mobile device.
The algorithm update, named Vladivostok, is currently just affecting search results in Yandex's Russian index, but will be rolled out to Ukrainian, Belarussian, Kazakh and Turkish users in coming months.
Yandex classes webpages as mobile-friendly if they feature vertical rather than horizontal scrolling, and if they exclude Flash, Silverlight and Java applets.
Webmasters can check whether Yandex considers their webpages to be mobile friendly by entering their webpage URLs into a special tool, which is accessible via the Yandex Webmaster toolkit.
Yandex has said that non-mobile optimised sites will still appear in the search results if they are the best answer to a very specific search query, however.
The search engine has also said that the algorithm take page load speed into account, with slow pages being penalised. Websites that redirect users to apps will also face penalties.