A (very recommendable) thing is that a page adapts to the different screen sizes of mobile devices, and that it shows an optimized version of the content with a different arrangement. But another thing is that when you access a page from a mobile device, it automatically redirects somewhere else but the site we wanted to visit.
These are techniques that some developers use often to improve their statistics, which take the user directly to e.g. apps marketplaces when they detect that a user is accessing their web from a certain kind of device.
It seems that this annoying practice could soon be over. Google announced recently that from now on it will start punishing these actions, which the company considers “frustrating experiences” for the user. Google will punish them regardless of whether this practices are intentional or not.
The punishment will include the possibility that the URL of the site is no longer indexed by the search engine, making it almost invisible to the public. In fact, Andrey Lipattserv, one of the people in charge of the search engine’s quality, said that they already have a team that deals specifically with detecting this kind of situations.
It is important to pay attention to this, because although many of these redirections are done on purpose (e.g. those that redirect automatically to app stores), in other cases they take place without the webmaster realizing what is going on. The web might be the victim of a hacker attack that is only affecting the mobile version, redirecting to spam domains. Another possibility is that an ads system is making these redirections automatically without our consent.
Google also recommends listening to the feedback provided by users, check regularly the different versions so that everything works as it should. For this we can use emulation options of different devices from some desktop browsers.
Another tip is to have a look at the data provided by Analytics, where we can detect suspicious behaviour in mobile traffic levels that can mean that something is not working properly.
If you want to optimise your page for mobile devices without incurring into malicious practices that can result in penalties, we offer you some advices that might prove very useful.