If you buy something from Amazon you've made a one-time exchange.
If you use WP Engine, you have an ongoing agreement with them to provide and support a service on which your business depends. A reasonable and literate person could construe that to be an affiliation.
If you use WP Engine, you have an ongoing agreement with them to provide and support a service on which your business depends. A reasonable and literate person could construe that to be an affiliation.