You start by seeding it with the name of a topic, several article links that you know are on topic, and links to profiles of people that you know focus on that topic.

FORBES: Is This What Tom Cruise Reads on Twitter?

The first name of Steven Bourne, the subject of a Home Front article in the latest Friday Journal about renovating a traditional home in Shanghai, was misspelled as Stephen.

WSJ: Corrections & Amplifications

Using Factiva, a Dow Jones-owned media-archive service, about 25 New York-centric newspapers, magazines, websites and blogs are scanned daily and scored based on what names are mentioned, the number of times the name occurs and the placement of the mention in the article, such as in the first paragraph, in a headline or caption.

WSJ: Methodology for NYIndex