Home automation is a broad term to describe everything ranging from making an A/V system easier to use, to full-on smart homes.
Home automation systems are normally installed by an AV integrator skilled in programming and system design. Integration is considered by most builders and architects to be more a subcontractor trade than simple home theater installations are. Many of the best integrators are members of the non-profit organization CEDIA, which trains and educates this growing field of ultra-high-tech IT experts.
A typical automated home tends to include a whole-house audio and video distribution system. These are often controlled by touch-screen remotes linked by RS-232 (or wirelessly) throughout the home, including in-wall keypads. Apple's iPad is being increasingly used in this regard.
Home automation systems also often integrate security, HVAC control, lighting, drapes, motorized or masking screens and much more. Home automation systems are often becoming Internet-friendly. Many integrators can make changes to a client's system remotely via wireless connection. Home automation knows no limits on the high side. If a client can dream of it, it is likely that an integrator can figure out how to make it work, assuming there are enough dollars to fund the project.