The Florida Department of Revenue determined that a platform software company should source its income from user fees and from its sale of services on a market basis, based on the location of the customer to which the services are provided. The platform software company provided a platform for developers to create and sell software applications, collecting user fees for access to its platform and for purchases from the platform. Florida law sources such sales to Florida if the “income producing activity” is entirely or predominantly performed in the state. Under the Department’s ruling, the income producing activity for the user fees is for access and for purchases, which occurs where the customer is located. Accordingly, the Department concluded that such sales should be sourced based on the user’s billing address. The determination of the “income producing activity” in Florida remains a hotly debated topic. Software service providers should take care to consider their individual facts and circumstances associated with Florida income tax sourcing.