With mobile browsers becoming more and more popular every day, mobile versions of websites are required to be easily accessible to all users.

You have no mobile site

Okay, this one is a little cheap, as your mobile site can’t suck if you don’t have one, but let’s be honest, this is probably one of the biggest faults you can make. Recent data states that mobile users make up roughly 30% of internet traffic. That’s almost 1/3 of users that may come to your non-mobile website on a mobile device, find it not user friendly due to various reasons and go to a competitors site instead. That’s a huge chunk of users to ignore for a fairly simple solution.

You have a mobile site, but you have content on your desktop site that is not accessible on your mobile site

This one is pretty self explanatory. Have you ever loaded a news webpage and get greeted with a message similar to “We’re sorry, this content is not available for mobile viewers?” That something that should never happen, and is a guaranteed way to have users bounce away from your site. Thankfully this is becoming less frequent. If nothing else, you should display the non-mobile site in its stead; showing something, anything is better than saying “we don’t want you to view our site.”

Accessing a mobile link redirects you to your mobile homepage

Ever followed a link from Google to a specific article on a website only to be presented with the mobile home page of that site? When that happens to me, I immediately go back to the search results page and go to another link. The way I look at it, I already did searches to find the content I want on a search engine, I shouldn’t have to do it again to find it on your site. If you automatically redirect mobile users to the mobile site, you should send them to the mobile content equivalent of what they were trying to access in the first place.

You have “download our app” pages or pop-ups

This is a slightly gray area. It’s entirely possible that you have a great mobile app that allows users to navigate your content much more effectively or that users don’t know about. In my opinion, it’s okay to notify the user once per visit that the app exists. There are still sites out there that pop-up the same notification on every page. This should not happen.

You have huge resources (extra sin, auto-loading / playing videos)

This is a huge no-no. With mobile websites, you need to consider a few things that you don’t need to with desktop users, namely that mobile devices don’t perform as well as desktop devices and if the device is using a mobile 3g/4g connection, they may have strict data caps to keep in mind. Auto-playing videos or other media heavy items can lead to unresponsive mobile devices and huge data usage. In general, mobile sites should be opt-in, meaning that the user needs to actively indicate that they want heavy parts to show, for instance by clicking/tapping on a video to play it. In addition, these heavy resources should be optimized for mobile devices; hi-def images and videos should be re-sampled to a lower resolution and you should try to use CSS and HTML5 in place of images and video if possible).