[ycitm]

Interestingly it looks like the "sways" do a lot of their layout calculations on the server. Resizing the window triggers a call back that returns what looks like a bunch of styling information (this div goes here, with this Z index, etc.) which would ordinarily be left to the browser.

Perhaps this allows them achieve more than they could with the browser's layout engine? Certainly an interesting approach.

(edit: wording)

[theatraine]

From their blog entry: "Sway’s built-in design engine takes the hassle out of formatting your content by putting all of it into a cohesive layout as you create. ... This is thanks to a lot of Microsoft Research technology we’ve brought together in the background. As you add more of your content, Sway continues to analyze and arrange it based on the algorithms and design styles we’ve incorporated."

It sounds like they're doing some more complication computation on the fly than typical responsive CSS. I suspect that it's related to some of the "Reading mode" work that they've done with IE.

[anigbrowl]

And think of all the browser intelligence they get by doing that server-side - very smart.