As of 21 April 2015, Google clamped down on non-mobile friendly sites, in favour of those that are fully mobile friendly.
Let us explain “mobile friendly”
Open your site in a browser. Make the browser window narrower, and if the shape and layout of your site does not change, and just goes ‘off the page’, it is not ‘mobile-friendly’.
Look at your site on your phone, if it goes to a “m.domain.com” type of web site, it is not ‘mobile friendly’. It’s just a mobile “version”.
Here is the article from Forbes. If you have any concerns, drop us a line.
Update 2020: Mobile Friendly Responsive Websites are pretty normal nowadays. At a time when there were concerns, it’s standard practice today. We still see some websites that have mobile versions which is a failure of the website design company. But we only do Responsive websites now, and have done for many years.