Proper home automation relies on two different controlling devices—a “resident device” and an “automation hub.” While there are products that include both functions, understanding the differences will aid your own quest to make your home smarter.
Home automation hardware is sort of like Wi-Fi Routers and broadband modems: Sometimes you can get both functions in a single device, sometimes you have separate boxes for each. Just as with those better-understood devices, resident devices and automation hubs have important differences I'll explain below.
A "resident device" is a device that is always on your network, and accessible from outside your network. Resident devices hang out on your network listening for when you send a request over the internet. Mobile devices like phones and laptops aren't good resident devices because they can come and go, you need this device to live on your network all the time.
Currently there aren't any dedicated resident devices, at least not that I've found after considerable searching. Most home automation hardware is either an automation hub (see below) or a hybrid, which is a device that lives on your network listening for commands but can also execute those commands.
So let's look at a home automation hub. These devices are the "brain" of your smart home, allowing for the automation part of home automation, and also enable smartphone access, putting the "smart" in smart home.
One of the most common hubs is the Wink Hub, available at Home Depot and other retailers. A similar option from Lowes is called Iris. You can also get the Insteon Hub, which works with a variety of devices. Lastly, there are SmartThings-branded hubs, but they only work with other SmartThings devices.
Home Automation Hubs from SmartThings and Wink.
As mentioned before, you can find hardware that is both a resident device, and actually responsible for executing commands you send. This tends to be a box that controls a single kind of hardware, such as the Philips Hue Lights hub, or the WeMo Link.
Philips Hue lights require a hub that is also a resident device.
So far I haven't mentioned the Apple TV by name, and that's because right now it doesn't practically fall on either of these lists. It is meant to be a resident device, and those features of HomeKit we saw at WWDC 2014 were resident device features. However, there aren't any devices out right now that take advantage of Apple TV's resident device capability. There is hope that will change soon, but as is always the case with Apple, we won't know until we know and until then it's all a guessing game.