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.

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.