Something I've picked up from reading about economics is the concept of "the margin".  It's a way of thinking about problems that more people ought to take into consideration.

What is "the margin"?  It's that space on a line, in the middle, between two extremes, where the transition from "yes" to "no" occurs.  If I offered you a million dollars for the computer you're reading this on (for broad definitions of 'computing device'), you'd probably take me up on the offer.  For 0 dollars, you would not.  Somewhere, in the middle, is a number where you'd change your mind from "nope, won't sell" to "well… sure, what the heck".  That is, loosely defined, a margin.

As an example, when people debate about "intellectual property", they often use terrible examples: companies like Microsoft, or performers such as Lady Gaga.  Those are bad examples because they are complete outliers, way off on one end of the curve.   It's hard to disagree with "so what if Lady Gaga earns a bit less revenue from her music, she's got plenty to live on" when you talk about copyright being a means for artists to support themselves with.  Thinking "at the margin" is about those bands that currently barely sell enough music to work professionally as musicians.  In scenario A, they are able to work creating music, thus creating more, and likely better music than if they merely pursued it as a hobby.  In scenario B, they fall on the other side of the margin and therefore have to get 'real jobs'.  This means that their music takes a back seat, and they produce less of it.

Now, copyright and company are a complex conundrum with many facets; my point is simply that when thinking about big changes, we should think what will happen at the margin, not what will happen to the outliers.