Web application is the umbrella term and websites are referred to as apps as often as mobile apps are now. There was a brief window where "app" was typically used just for mobile apps (due to apple marketing the term) but that's no longer the case. Doesn't matter anyway if it's an app, a service, or a website because the concept of "if it's free, then you're the product" refers to all of those and iirc was first used referring to the way google and Facebook (the websites) make money off user data.