There are always two options: creating a mobile app or web application or creating a mobile website or use web responsive design.
Another difference in terms of support in web design is the format. If a catalog we know exactly the size of the paper in web design we have no assurance that display type used by the client. That is, neither the size in inches or monitor calibration. Excluding the type of browser you are using (Explorer, Chrome, Opera, Firefox ...)
Fortunately, one of the latest web design problems have been solved with new connections. I refer to the weight of the images, which work with a few kb, and how not to Mb in graphic design.
The need to incorporate dynamic language to some extent conditioned us web design web site.
Finally, the concept of web usability web design deeply conditions. We previously studied as placing the graphical elements to facilitate intuitive navigation through the site.