[pdabbadabba]

> And I hate when people use efficiency when they mean speed.

Except they're usually right. "Efficiency" is not just a measure of algorithmic complexity. Something is more efficient if you are able to do more of a desired activity at the cost of fewer resources. The resource in question varies.

Yes, one often in computer science focuses on algorithmic complexity as the resource to be economized on. But time and power are also perfectly reasonable resources to have in mind. In fact, they are the resource that most audiences will naturally assume when they see the word "efficient" standing along, without further explanation.

I think GP is probably wrong to criticize as well -- making code more efficient [or, if you insist, fast] makes it easier to support more users that it could support otherwise. Is the ease with which a system can support an additional user not the very definition of the word "scalability"?

Of course, there are more powerful, and more specialized techniques for improving scalability, but that doesn't mean the author is wrong to suggest that speed improves scalability.