Usability 
OSNews is a web site that covers just about every operating system past and present. There are the expected articles on the latest Microsoft Vista delay, the backlash against the Intel Apple and new releases of various Linux distros, but to me the real heart of OSNews is it's coverage of obsolete and obscure OS's. It's a great site for anyone who has been playing with computers for a while and wants to know what's up with the old systems like Amiga or BeOS or even Apple II DOS these days. The site is also a must read if your are interested in upstart and underdog modern OS's like Syllable or SkyOS. OSNews strives to cover all operating systems including embedded, mobile and PDA OS's. There are quite a few mobile related articles. There's even coverage of mobile and PC browsers, which makes sense as browsers are now computing environments and performing many of the functions traditionally associated with operating systems.
To support their readers on a wide range of systems, OSNews has versions of their sites that are viewable on virtually any browser including mobile browsers. This page describes the support for numerous old, text-only and mobile devices. Using browser detection, OSNews will deliver one of four different versions of the site.
1) The normal web version at http://www.osnews.com/ with advertising and large images, formatted for modern web browsers with horizontal resolution of at least 640px.
2) A lighter but still full featured cHTML version for most other browsers including text-only browsers like Lynx, older graphical desktop browsers like NCSA Mosaic, PDA browsers and most mobile browsers (first two images). This version contains almost all the content of the web version including the full text of all the News, Features, Interviews and Editorials sections. On mobiles the site will display without horizontal scrolling on any browser with at least a 128x128 resolution and the ability to handle pages up to 32 KB in size. The mobile page is at the same http://www.osnews.com/ url as th PC site. It is displayed if a mobile, text only or limited browser is detected. There is no alternate url if your device isn't detected properly. If that happens OSNews would like you to contact them with you devices User Agent string which you can get by visiting this page so that they can add it to their browser detection routines.
3) An even lighter cHTML version at http://www.osnews.com/jphone.php consisting of a main page containing titles and links to the light version of the 15 latest items (last image). SonyEricsson browsers get this page as do most phones on Japan's J-Phone network as both these browsers have page-size and other limitations.
4) Finally there is a WAP1 page for wml-only phones at http://wap.osnews.com/. It has the same top 15 stories but the links are to short summaries of the articles which in turn contain links to the light cHTML full text version.
Of these four versions, the second, full featured mobile one is the most interesting to me. It's not an xhtml-mp site, it's cHTML. That makes sense as the page is intended for use with a wide variety of browsers many of which have no support for xhtml and CSS. cHTML ("Compact HTML") which is usually associated with i-Mode is a subset of HTML 3.2 and is displayable by just about any browser except wml-only ones. Layout is done using tables rather than CSS. While tables have a bad reputation these days and typical table-based desktop sites render poorly on small screens, OSNews uses tables with a width of 100% so they scale to fill the screen and are mostly one cell wide (except for a 3x2 navigation menu) to create a nice stacked and bordered presentation of the articles and their titles.
I was amazed at how well the site displays on mobile devices. I've always though that you had to use xhtml-mp and CSS to achieve this level of quality on wap2 devices. But here's a site done in HTML 3.2 with a table based layout that is both very attractive and highly usable on everything from fairly low end phones to old Palm OS browsers to Lynx. I asked OSNews about this and got a great reply from Eugenia Loli-Queru who not only writes for OSNews (frequently on mobile topics) but also designed the mobile pages.
Eugenia says,
"cHTML is much more compatible than CSS and XHTML. I mean, look at the big-4 desktop browsers (IE, Safari, Gecko, Opera). Writing anything in CSS usually doesn't render the same on all 4. The situation is even worse on mobile phones where the browsers have very limited memory and CSS requires much more memory and CPU to compute than plain HTML because the layout is not "fixed". For example, saying that a table is 80% instead of 200pixels requires a lot more cpu to compute, even if it sounds trivial to web developers. My husband works for Openwave.com and he is the browser architect of the Openwave browser. He has taught me how to avoid such problems. :)
Then again, think how a browser is created. The developer has to start from the basics. And that means plain HTML, then some CSS, and much later some javascript. Most browsers only manage to do well only the first and easiest part of the whole thing: plain HTML. And this is the reason why cHTML will always be the best choice for compatibility between browsers (including desktop browsers). XHTML and CSS are cool on paper, very interesting technologies, but in the real-life mobile web, they are too expensive in terms of complexity, memory and CPU required and for the time being, it's best to be avoided."
When you look around the mobile web today you will see that many mobile site designers are still building new mobile sites with a subset of HTML rather than xhtml-mp/CSS. The 31 new mobile sites that I wrote about recently are HTML, as are MacRumors, Windows Live and Mobile MSN.
Incidentally there's a lively debate, with Eugenia a major contributor, going one over at PocketPCThouhts on this very issue. It started as a discussion of the merits of the new .mobi domain. One of the requirements for .mobi sites is to use xhtml-mp, CSS and no layout tables.
As a counterpoint, take a look at this showcase of supposedly .mobi compliant sites hosted by mTLD, the .mobi registrar. I say supposedly because several aren't actually xhtml-mp (OK, they're xhtml-strict - close but no cigar) and one, CityGuide.mobi is actually cHTML! I notice that most of these sites are very plain and dull visually compared with OSNews.