What is the relation between Internet of Things based smart home, and web-based home automation?
Call it two ends against the middle, which is to say IoT consists of the individual, connected hardware devices and interfaces remotely based in the home. Whereas, SaaS (Software as a Service) platforms online function as integration and control for the connected parts. In an ideal world, or perhaps future scenario, this semantic definition, or thin line, would be more or less transparent to the end user, or consumer.
See also my Quora answer: