Google took a definitive stance on the situation last June. Google stated that sites should serve all devices with the same set of URLs, meaning each URL should deliver the same HTML to every gadget accessing the page using only CSS to render the information.
Now we're talking about one version of your web site delivered to phones, iPads, tablets or laptops. Google has said their piece and the chore of updating multiple platforms just disappeared from your to-do list.
This isn't difficult to understand. Your website will return better traffic numbers if it has only one URL for each page as opposed to the same page represented with multiple URLs. Publishing a mobile website vs responsive design configuration only dilutes your traffic and the all-knowing search engines will notice.
Staying with the simple-to-understand theme; we find that search engines don't index apps. If you have an app instead of a site with a responsive design, your site does not benefit from mobile visitors and the search engines can't find/explore the information on the app. A responsive design that delivers well-designed information on a mobile device will be found and indexed. Plus, the crawler, used by search engines, doesn't need to work as hard.
Statistics from Google's Mobile Ads Blog show 79% of shoppers now use their phone for information while shopping, 70% use their phone in the store and 77% have directly contacted a business by mobile. The message here is mobile shouldn't be some add-on to your website and neither should your ads. As we explained, usage and traffic on a mobile app won't be indexed on search engines. If you're using a pay-per-click campaign, Google may not be able to place ads in your mobile app - like when someone is using their phone at the store. Deploying a mobile website vs responsive design is now costing you money.
Have you noticed sites attempting to cater to tablets these days? Creating a site that caters to one visitor alienates another. Make your site "touch friendly" for the tablets and still usable for PC users with CSS and responsive design. Make buttons and calls to action bigger while keeping them normal on a desktop.