That's not the same thing. Burn Notice (and more notably, 24) use that technique for very short periods of time to change things up. And during that time there is never anything important going on in any of the 2 scenes--no one is going to risk half the viewers missing a relevant plot point just because they happened to be focusing on the wrong half of the screen at that moment.
Try going to Fry's and finding a spot where they have 2 TVs next to each other that are showing different channels. Try just watching one of them: It's maddening. To me it's equivalent to animated ads on web pages--it just makes it impossible to concentrate.
But with Burn Notice, they don't expect you to concentrate on just one of the scenes... instead, you look at both or all of them at once, and you get a pretty good idea about what's going on in all of them. This is possible because meaning-wise, video is usually very sparse; lots of people "watch" shows while doing other things, and still have a sense of continuity about the story the show is telling. I also find this a bit distracting, but many people I know seem to use this as the default paradigm of watching TV.
However, the thing I find interesting is other people in the comments here have mentioned that they just look at the center and take in what's going on on both sides, which is exactly the same technique, and Facebook timelines are sparse in the same way that video is. It's easy to get a sense of what your Facebook friends are doing with a quick skim, without fully concentrating on any particular post. During this skim, your attention might be drawn to a specific post, but if it's not, you've absorbed a high-level overview and moved on, without having to read each post individually.
What do you mean? Burn Notice typically has two plots running at once (the plot that advances the overall story arc, and then the per-episode plot where they help someone), and they like to switch back and forth between the plots frequently, but they never show them at the same time.
Lately they've used split-screen to show simultaneous actions by different people. It works rather well, because while the videos show different actions, they both fit into the same coordinated plan.
For a few seconds at a time, during transitions between scenes or in the lead up to advert breaks. Synchronicity of relevant actions is minimum - ie a car driving, while someone sits in a room. the other two may be 2 sides of the same phone call.
There's not really ever 2 concurrent plots happening simultaneously.
But some TV shows (Burn Notice, for one) do this frequently. It works pretty well.