— Massimo Vignelli.
Design is NOT about the way things look or for that matter even work. Design is about that inherent way of thinking that makes you question, understand and then perform actions. So yes, if you are actually good with graphic design at a fundamental level, you are also good with web or iOS or any other new screen devices where elements need to be arranged and form a visual relation.
If there is any one designer who says they are good with mobile design and not web or vice versa, beware, either the person does not their own potential or does not get design.
Designing for any medium has their own constraints and designing for that medium is designing within those constraints.
I think if one can design a user interface for Android, there should be a reasonable overlap with the skills required to design a user interface for iPhone :)
Web: sRGB, design with technology in mind (grid systems and other), different views on the same design (mobile, monitor resolution), things that are consistent across browsers.
Mobile apps: platform convention, touch oriented.
I suppose print takes the cake in terms of annoying details, however.
"There is nothing special about the web that makes it more or less challenging than designing on an iPad. They are just different."
Differences are exactly what makes something special. Specialists are those people who have in-depth knowledge of the differences and know how to make use of them ... and know how to make use of those differences now, not after they experiment and figure things out from first principles.
So advertising for an OSX designer, or an Android designer is a sound decision. I've run a team of Solaris sysadmins and yes I could have hired Linux sysadmins (unix is unix as the cliche goes) ... but I won't - Linux admins may know the fundamentals of unix, but I want people who really understand Solaris and how to get the most out of it. And I don't want to wait whilst a Linux sysadmin learns the differences between them.
To be a little critical of the author, it doesn't sound like he has much experience as a designer - the blog post sounds like something written by someone who doesn't know what he doesn't know. Isn't the saying that the 'devil is in the details' (or differences) ... I would have thought that a good designer would understand that and never argue that all you need is generalist knowledge.
Oh, wait - perhaps knowledge of the medium and its constraints is important on occasion.
What I think he is missing and why I think he is basically giving bad advice is that sometimes you have to label yourself in such a way that you minimize friction from a getting hired point of view.
Many clients believe that there is a difference between a good Wordpress designer and a good iPhone designer, but obviously the truth is that if they are anything worth they don't care what they have to design for.
Design is not simply how it looks but as much how it works.
If I am making an iPhone app I'd like a designer who has experience with it. So it is the difference between "I want a designer with OS X experience" and "I want a OSX Designer". Aren't they almost one and the same?
But we're beginning to enter an era where if you run a business and your adement about having a well-designed product, then you should be willing to take the time to develop a cursory knowledge of the industry. Be able to differentiate between buzzwords and the all-too-familiar "insert development platform here" designer. Although his argument is a bit understated, Ben's point is clear: don't waste time with people who aren't absolutely head-over-heels about design. They cost more and sometimes require more resources, but the return on that investment will surprise most people. Even if they don't believe it, people respond to good design.
Coming up with a great looking photoshop comps can be achieved by a lot, but creating a consistent user experience is the most critical.
I am not sure that all the 'designers' do understand that. And this is an area where Apple is well known to spend a lot of time for all their apps.