One of the unique challenges with the web is that it is a portable, scalable medium. Ideas that work in X pixel ratio don’t always translate in larger or smaller spaces. We (and the industry on a whole) are striving to make our site(s)  snap to mobile - or any other “space” where users access content-  seamlessly, as content viewers dictate how and where they access content. [Tangent: SHOULDN'T it work that way? Shouldn't I be able to access content where and how I want? Books, music, etc...just replace content = art] This juxtaposition of ideas in limited pixel space becomes increasingly relevant in our user-centric world and I am just fine with that.

The preceeding is more of a pre-amble; what is at hand is how to explain to designers used to a print world that the web is living and breathing. Fonts may be spec’d to be X size, but, users can and will choose preferences. Design must scale, physically, and that is a hard concept to begin with, however, the real kicker is scaling the purpose to begin with; the solution must be flexible. This is where core creativity comes in- the rest is just production/implementation.