If you read the KVS wiki thread you'll have noticed that application doesn't pay anyone for the GDS data. KVS asks for donations from users in exchange for which they get access to fare inventory data from the airlines. How does KVS get the data? Well, from a variety of sources. It has created dummy accounts with various travel service providers from which it sweeps GDS data, and it asks you to enter your own FF account information so that it can question that airline/alliance search form to scrape that data. Every so often it goes down for a while because an airline or travel service provider has noticed hundreds of thousand of requests through its system. KVS then finds a new one.