SEM Firm Applies Century-Old Linguistics Law

While every search marketing or SEO firm has its methods and formulas, archaic math and linguistics theories aren’t often among them.

Yet at least one SEM agency, Commerce360, claims to make active use of a formula called Zipf’s Law (define). The empirical law, originally proposed in the first half of the 20th century, states the most common word in a body of data occurs twice as frequently as the second most common word, whose frequency is double the fourth most common word.

Using it, Commerce360 says it can assign or predict the frequency of vocabulary and keywords surrounding a product or service. It does so by listing words related to the brand, ranked in order, and then graphing them to the formula. The formula’s curve follows a similar trajectory to the long tail, and is able to identify the head tail and mid tail.

“It turns out all of these long tail pictures follow the same swooping curve,” said Bruce Ernst, VP of product management at Commerce360.

Commerce360 has a computer program to do the heavy lifting of Zipf’s Law. After calculations, the team can determine where a word falls in the long or mid tail, and what terms might be missing from its graph. The company added it doesn’t “set it and forget it” once keywords are calculated, but rather repeats its process at regular intervals to determine whether they’re still appropriate.

“The law predicts certain words will decay at a certain level,” said Ernst.

Commerce360 EVP Michael Smalls says the program is better than 95 percent at its accuracy level.

Commerce360 was founded three years ago, and has been in commercial operation for about a year and a half. Clients include American Eagle, Comcast, Nautica, Liz Claiborne, and Franklin Mint.

Ernst said some terms can be expensive, and might not make sense. “You can buy your relevant words and they won’t do you any good if you don’t have the right vocabulary,” he said. A second mathematical formula, the Lorenz Curve (define) is used to show how income distributes across the portfolio, executives said.

Ernst and Smalls said they originally used Zipf’s Law to study an entirely different medium, using it to expose keywords commonly used in spam.