Now that I sorted out this site's mobile problems, I feel authorized to complain about mobile issues on other sites. Here are my top four pet peeves.
Aggressive App Promotion
“I’d LOVE to download your app instead of going to the webpage I just tried to visit!”— No-one, ever. No-one in the future either.— Graham Linehan (@Glinner) July 10, 2012
You go to a site and get blocked by a dialog box that encourages you to download their app. When I click on a link or type a URL, I am sending a pretty clear signal that I want the content that is on the other end. I am not looking for another app to install.
If you want to promote your app, use a banner ad slot to make a subtle suggestion. Don't put up an interstitial that breaks the flow. A few sites do this nicely by putting a small floating tab on the bottom right of the page.
Speaking of dialog boxes, don't put them on your mobile website at all. If you feel like you need a dialog box, make sure to design it for mobile by making the buttons extra big. Those tiny x's in the corners just don't cut it.
The writing has been on the wall for a long time now and, now with Android Jelly Bean dropping Flash support, there is no denying it. Flash is dead on mobile. Don't use it — especially if your site is for a restaurant or any other destination for people on the go.
Disjointed Mobile/Full Experience
If your content is any good, it will be shared between users on all sorts of platforms. Someone might first encounter the content on a mobile device and then want to continue reading on the full experience. To facilitate this, make it easy for a user to jump between content views.