How do you use "Hot Words"?

[FSNet]

How do you do what I call "Hot words"? Lets say you have a website and for example you are on a page called Travel and it mentions some other stuff and whenever you have words like "U.S Airways" or "American Airlines" it will automatically make it into a link and direct it to that file in the directory on the airline.

I guess this is basically just inserting a link whenever it finds a specific word? Thanks!!