Google announced on the webmaster blog that they will now penalize, through manual actions, sneaky and unwanted mobile based redirects. Truth is, Google has always taken action on sneaky, fraudulent and unwanted redirects, but Google is now making it clear - they will do the same on the mobile front.
Why are they making it clear on mobile? Well, Google does allow you to do redirects to slightly different content on mobile. So if you have a desktop page with a lot of content and navigation, Google is often cool with you dumbing it down for mobile users - as long as the page is similar enough. But if you send someone to an irrelevant site, then you are now in trouble, Google says.
Google said:
Optimizing the smaller space of a smartphone screen can mean that some content, like images, will have to be modified. Or you might want to store your website’s menu in a navigation drawer (find documentation here) to make mobile browsing easier and more effective. When implemented properly, these user-centric modifications can be understood very well by Google.
But this is not okay:
The situation is similar when it comes to mobile-only redirect. Redirecting mobile users to improve their mobile experience (like redirecting mobile users from example.com/url1 to m.example.com/url1) is often beneficial to them. But redirecting mobile users sneakily to a different content is bad for user experience and is against Google’s webmaster guidelines.
Google realizes that sometimes this happens unintentionally, like with hacked sites and/or ads that take over the site. You are still responsible for your site and Google will issue a manual action when this is done unintentionally, but Google is warning you to register with the Google Search Console so you can stay on top of these issues. Google listed three ways to be notified of issues:
(1) Check if you are redirected when you navigate to your site on your smartphone
(2) See if your users are complaining
(3) Monitor your users in your site's analytics data
I spotted this last night on Johannes Mehlem Google+ post, but now the English version is up.
Forum discussion at Google+.
