A few of the responses here and in the blog comments are up in arms about your suggestion to treat mobile and desktop users the same. The comments that intend to contrast the differences between processing power, dimensions, and available network resources of "desktop" versus "mobile" devices are predicated on the notion that users do want you to send gobs of data that consume more resources when they are on desktop machines. In general, however, they don't. Witness the comments in "Your social widgets are losing you visitors right now" (http://news.ycombinator.com/item?id=1771607) and the popularity of Readability. (http://lab.arc90.com/experiments/readability/)

Something I think (self-apologetic and self-described) Web "designers" and "UX experts" in the West don't realize is that bandwidth caps still exist even for home use, and in some places they are the norm.

Given the reactions, it seems when people read the suggestion "serve the same content to all browsers", they see "serve mobile users the same content that you serve on your created-with-the-desktop-in-mind ('full') Web site". Perhaps this should be reworded to explicitly say the inverted form: "serve the same content on your full Web site as you serve on your mobile Web site." Surprise! Mobile users aren't the only ones who like to view content created with ease-of-consumption in mind.

[Cue dissent pointing out that I did use the word "consumption", followed by some bullshit suggestion like "Mobile users are primarily consumers while desktop users usually want to engage with the content." Such a suggestion ignores that a non-trivial part of the mobile-use population does seek to interact similarly while on a mobile device, as well as the non-trivial part of the desktop-use population that is mostly only ever annoyed by the extra cruft that gets sent down because they weren't recognized as being on a mobile device. This is due no small part to the fact that there are no such things as a discrete mobile-use population and a discrete desktop-use population. It's the same population coming to the table with varying modes of access.]

And finally, here's something that I've been trying to hammer on for a while. I have a not-modestly sized screen. I should be able to manage applications and Web pages so that I have multiple things visible on the screen at the same time, such as two pages that I'm cross referencing side-by-side; or a page open with some other application visible at the side; or, say, Songbird—displaying lyrics from the Web or band information from Wikipedia—in a way that doesn't take up most of the screen; or any other application which seeks to similarly integrate content from the Web but doesn't conform to the now-ancient assumption of one big browser window displaying the page contents over most of the screen.

Now with the proliferation of wide screens and increasingly large displays, I should be able to consume things in this way, and it should be an option for you to build these types of applications without annoyances like requiring horizontal scrolling.ⁱ Instead of being able to take advantage of these opportunities, we get questions asking, "Can we require even more screen space for our Web pages now?" (http://news.ycombinator.com/item?id=1736808)

1. Horizontal scrolling essentially defeats the attempt to prevent from toggling between multiple windows, because it's ultimately an attempt to prevent from spending too much time managing the viewport of content, rather than spending it acting on or in response to that content.