Farhad Manjoo has written a condescending article for Slate about how we have short attention spans online:

I’m going to keep this brief, because you’re not going to stick around for long. I’ve already lost a bunch of you. For every 161 people who landed on this page, about 61 of you—38 percent—are already gone. You “bounced” in Web traffic jargon, meaning you spent no time “engaging” with this page at all.
I better get on with it. So here’s the story: Only a small number of you are reading all the way through articles on the Web. I’ve long suspected this, because so many smart-alecks jump in to the comments to make points that get mentioned later in the piece. But now I’ve got proof.
You Won’t Finish This Article – slate.com
The article fails to mention sites – like Slate – that arbitrarily split articles into multiple pages. I have to imagine that a huge percentage drop off after page one, which would have had a massive impact on the findings (whether secondary pages were included or ignored in the stats!) so it’s odd not to mention it.
(The big spike at 100% on the ‘percent of article content viewed’ chart is for photo stories – most visitors will scroll through an entire photo essay.)
It’s also worth pointing out that Slate’s multi-page article design actively encourages readers to leave a comment before reading the whole article by effectively placing them in the middle of the article.
Sites are partly to blame for making their own content the least interesting thing on the page
The blame for the flighty behaviour of readers can also be at least partly attributed to design choices made by Slate and similar blogs. In addition to the main navigation, the top of the page is overloaded with calls to action to other stories, Facebook, videos to watch, distracting ads etc. Later in the article Manjoo complains that people share an article before reading it, but the sharing icons are right there at the start of the article.
Meanwhile, the Slate article itself is visually unappealing. The photograph at the top is both unnecessary and entirely uninteresting while the article is small text, thankfully broken up by colourful charts.
Of course, people are fickle and easily distracted, including myself. I follow many links only to decide when I arrive that I’m not that interested. Perhaps as readers we should be more disciplined – some of these uninteresting stories we click on are important – but these sites are partly to blame too for making their own precious content the least interesting thing on the page.