I can’t shake this nagging feeling that we’re changing our focus from “mobile context” to screen-size thinking and responsive design so quickly that our users won’t know what hit them. Although I fully agree with articles like Mobile Context Revisited and Design Process In The Responsive Age, I think there is a missing step we haven’t explored enough: how to change the mental models of users who have become used to separate sites on their mobile phones and desktop computers. Let me illustrate with an example.

During usability testing last week I noticed an interesting trend. It was dormant the whole time, but I just couldn’t put my finger on it until one participant explicitly articulated the problem. I asked her if she has ever visited the e-commerce site we were about to use. She told me that she’s never gone there on her desktop, but that she has browsed the mobile version of the site on her BlackBerry¹. So far, so good.

But then she mentioned that when she found a product that she liked, she decided to switch from the mobile version (.mobi) of the site to the desktop version (.com) — while still on her phone — to try to buy it. Her reason? She assumed that the desktop version of the site will have more information about the product than the mobile site has.

The rest of the story gets even bleaker. She tried to force the .com version of the site, but her BlackBerry couldn’t handle it — she tried multiple times and it just kept hanging. So she gave up and never went to the site again.

The experience highlights a few assumptions made by this participant:

• She assumed that the site will have separate mobile and desktop versions.
• She assumed that these two versions will have different information on them.
• She assumed that it is up to her to decide which version will best suit our needs.

Can we blame her for these assumptions? Isn’t this how we trained her to think about mobile sites vs. desktop sites? We kept building sites with reduced feature sets on mobile phones because we didn’t want to overwhelm users. We taught users that mobile sites are inferior versions of their desktop counterparts, and now we have to live with the consequences.

Now, fast forward to the future we’re all driving towards: fully responsive sites that don’t abridge content, but adjust to the screen sizes they are being served to. Considering this participant’s assumptions, you can imagine how confusing a site like that would be to her. She’ll wonder where the mobile site has gone. She’ll wonder what content she’s missing. She might try to enter .mobi and not know why the thing keeps going back to .com. She (and millions like her) has never heard the term “responsive design”, and couldn’t care less about it. We’ve cemented users’ mental models over the past few years of mobile-specific sites, and it’s going to take time to change that.

So, what can we do? When we build responsive sites, we need to communicate to users that they don’t have to worry about finding the mobile site any more — everything they need is right there. This can be as simple as a message on the home page, or relevant microcopy at key stages of the journey, like on a product page.

I’m not trying to stand in the way of responsive design or screen-size thinking over mobile context thinking. But I am arguing that most normal users will be confused by this trend, and we need to manage that. Because we don’t want incorrect user assumptions to cause lower-converting sites that end up killing organizations’ commitment to responsive design.