I've found that I'm using this feature much more than I thought I would in arc. Before, I'd figure that it's the same as opening two windows side by side. It's not, having it as a built in feature opens up a lot of things. Opening an article on HN and the comments on HN side by side, for example. I NEVER did that before, now it's second nature.
I think this style of browsing really shows its strength for research and review type tasks. Maybe I'll research what it would take to write an extension to implement some of these ideas.
