Some curmudgeons will tell you that you're browsing away because you have a child-like attention span, growing ever more attenuated by Google and Hacker News and that newfangled Rock and Roll. I'd like to give you a bit more credit than that.
I believe that you are a highly discerning informavore: knowledge is your prey, and you are merciless in its pursuit. You don't browse away because you have a tiny magpie brain—you are locked on to the "information scent," and you will follow its lead until the Nature Channel-tastic end.
This is where the journalism lesson comes in. Remember the Inverted Pyramid? The concept is that you lead with the important part of your article because your reader may abandon you at any time—it's proof positive that people have had short attention spans for at least as long as there's been writing. The basic Inverted Pyramid story goes something like this:
Thing you need to know.
So here's my big idea, the one I would have put at the top if I hadn't slept through that J-class: The Inverted Pyramid is actively driving away your users. The further you read into an IP article, the weaker the information scent gets. This probably mattered less in the heyday of newspapers, because the fastest way to get more information about a topic, assuming that you cared at all, was still to read the article in its entirety. What else could you do, drive to the library? Put on your weight lifting belt and crack the Encyclopedia Britannica? Even if you were certain that better sources existed, the best value-for-effort was still to finish that article, diminishing returns and all.
On the web, everyone knows where to pick up the trail to better information the moment they lose the scent. And maybe that's ok! Let's face it, lots of blog posts contain just one good idea, which could have been stated succinctly. Then its just the author typing because he likes that clicking sound. Heck, plenty of blog posts contain zero ideas, just a link bait title followed by backpedaling, trolling, or fanboyism. Your information senses are serving you well...
...until they aren't. The dark side of this is that we're all building up habits that support the one-idea article. When a really intricate idea needs to be transmitted, the author is likely to lead with the (not yet supported) core, and the reader is likely to expect that if that core doesn't make sense on first contact, it's all down hill from there.
I did wake up for the part of the class about "you need to tell 'em what you told 'em" so here's my formulaic conclusion: The Inverted Pyramid is actively driving away your users (and maybe that's ok!). If you've really got one clear idea, lead with it and people will leave when they get full, or when they think they're more likely to find the next big idea somewhere else. If you've got something complicated to get across, you're better served with a format that feels as little like the Inverted Pyramid as possible so you can build the scaffolding before you drop your ton of knowledge. Either way, your audience will thank you.