Google recently updated its rules regarding how results are presented for SEO, Search Engine Optimization. In April 2015, the algorithm was changed and one of the main points from this involved making web pages compatibles with mobile devices such as SmartPhones and Tablets.
Things to look out for your website to do:
- Adapt menu and elements according to the screen is being looked at from.
- Give enough space between elements and avoid small links that could cause confusion if they are being seeing from a small device.
- If you recently lost positions in Google, or if you just want to improve your SEO, make sure you check if your website meets all mobile-friendly requirements. Here's the link for that, https://www.google.com/webmasters/tools/mobile-friendly. If you get an error message, tell your provider about this so it can be corrected.