The Yelp project did not work out at all well. About 20 customers registered with Yelp and entered positive reviews, but then Yelp deleted nearly all of them. Folks have explained to us that Yelp only publishes positive reviews on the pages of companies who pay them to be listed (flight school owners are famously unwilling to part with money!).
The sentence preceding the excerpt you quoted is relevant. Phil wrote, "We did this recently by asking customers to go to Facebook and Yelp and write reviews of East Coast Aero Club." But Yelp frowns upon businesses that do that:
Q. "Should I ask customers to write reviews for my business?"
A. "While we understand that there is a temptation to solicit reviews from your customers, it is not something we encourage. [...] If you do ask your customers for reviews, please be prepared for the review number fluctuation that might follow."
I must admit, I was expecting this piece to be ironic (especially after describing the book as a "lame sequel"), or to have a punch line that they applied all of this and sales dropped 72%.
So I had to re-read it with a different mindset, and there's a few tips I can take away.
Data points accumulating.