Mobile version of the site – SEO WIKI
The mobile version of the site is a separate site from the main one, designed specifically for working with mobile devices. Most often – a stripped down version of the main site.
For example, this is the mobile VKontakte site:
Creating a mobile version of the site improves the position in the search, but it is perceived by search engines as a separate site, and this changes the approach to promotion. You can check the mobile version of the site using special services from search engines:
Google Optimization Check for Mobile and WebPageTest.
Checking mobile pages in Yandex.Webmaster.
Or using third-party services:
Read more about responsive design, its advantages and disadvantages in a special article about the convenience of sites for users of gadgets.