I recently placed Emphasis on this blog. It’s a fantastic deep-linking tool by New York Times developer Michael Donohoe. Installation was easy, thanks to a WordPress plugin by Ben Balter. Now, anyone can link to a specific paragraph of my blog and highlight any sentences.

To get started, hit shift twice. I love that. Ryan Sholin noted today that he had also installed Emphasis, and it occurred to me that as the tool spreads, double-tapping shift becomes a sort of shibboleth: Are you enabled for deep links? And if the answer is yes, pilcrows appear.

At that point, you can link to any paragraph by clicking on its pilcrow. Highlight by clicking on a paragraph and then any sentences within it that you wish to emphasize. Your new URL awaits in the address bar.

Emphasis is the coolest development in networked reading since the Open Bookmarks project. It was helped along by Dave Winer, who has enabled paragraph-level links on his blog since 1999; Jay Rosen, whose adoption of them last fall seemed to give the form new life; and Daniel Bachhuber, who created an early WordPress plugin. Companies like Diigo and ShiftSpace have made progress with Web highlighting.

In open-sourcing the JavaScript code for Emphasis, Donohoe hinted at one direction in which this could go: popular highlights.

You may know I’m obsessed with the passages that are frequently highlighted by Kindle users. There’s an RSS — or, ahem, any interested developers, JSON — feed for that. Lately, it’s been surfacing passages from The 4-Hour Body and an intense, World War II yarn. Stuff like:

The paradox of vengefulness is that it makes men dependent upon those who have harmed them, believing that their release from pain will come only when they make their tormentors suffer.

Now, yikes. These popular highlights are not generally my favorite reading. But the presence of this agonizing sentence in my feed indicates that some large number of Kindle users — hundreds, it seems — were motivated to highlight it. That’s cool.

What motivates a user to highlight? When I last wrote about this in 2009, I said, “I’m not sure precisely what that’s measuring, but it feels like engagement.” Well, sure, but it also feels like importance.

Before the holidays, I lent out a few Kindle books because now we can. But I wished the loaned books I got in return came with the owner’s highlights and annotations (on toggle, of course). Couldn’t Amazon facilitate a secondary ebook market in which the used goods, along with their insightful notes, are actually more expensive than the originals?

All I mean is that deep links and highlights are value-add features. As users highlight the Times, they suggest what they find important, what piques their curiosity. Apture is also doing good stuff in this space.

Robin Sloan sees a comeback narrative:

And it seems to me that it’s actually an argument, in code, for the good ol’ fashioned open web—the web of pages and links. It’s like: “Slow down, App Store! We’re not done with this thing over here. We still have work to do.” Maybe it’s a futile argument—maybe the era of earnest linking is waning, and that’s just the way it is. But you never know. The web has surprised us before.

Just tap shift twice.