Steam on your tv. That's pretty much all there is to it, really.
I already mentioned a couple of weeks back that Valve is rolling out a new functionality for Steam: Big Picture. Basically, this mode allows a computer to be hooked up to your television while still providing full Steam compatibility with the larger resolution size. This week Big Picture went out of beta and into public release.
Basically, Big Picture uses a more controller friendly GUI that allows users to navigate and maintain a decent level of compatibility while still allowing things like text input and the like. This is aimed at a somewhat more average user level, as there has been nothing in the past stopping anyone from connecting a computer to their tv anyways and playing through the screen.
What's meant to appeal here is the ease of use. Valve is touting the whole "you just need an HDMI cable and you're pretty much good to go" aspect of it. Many people have probably been somewhat reluctant in the past to use their tvs in such a way, but Valve is trying to make this setup as user friendly as possible as a way to gently guide people into the transition or at least coax them into trying it out when they might not have otherwise.
That's probably part of the reason why a slew of controller friendly games have also been discounted to celebrate the launch.
Big Picture can also be used on any regular computer, although doing so I would think defeats most of the point. Still, I guess if you want a more console based experience without actually using one that this might be about the closest you're going to get.
More than anything, it seems to be the fact that it's Steam that is meant to draw users in. There's no hassle of having to setup new game libraries or develop new friend lists; it's the Steam that you know and love, just on a tv instead of a computer. Admittedly, that's both its greatest strength and its greatest weakness.
People who already use Steam on their computer and have no reason to put it on the tv won't really be compelled by any of this, although they may take advantage of some of the discounts on games to pick something up. However, since this is a free service anyways Valve pretty much has nothing to lose from this anyways. Positive word of mouth from them coming up with another neat feature is likely all they're really expecting out of this, and it seems guaranteed that's exactly what they're going to get.