Calculators are awesome, but they’re not always handy. More to the point, no one wants to be seen reaching for the calculator on their mobile phone when it’s time to figure out a 15 percent gratuity.

While presenting “Reporting and Analyzing PPC Campaigns” at SES New York last month, I noticed that many participants were interested in learning more about how to meticulously analyze campaign ...

If you’ve ever taken an algebra or physics class, then you’ve met a parabola, the simple curve that can model how a ball flies through the air. The most important part of a parabola is the vertex — ...