Remember the furor that erupted on the web and the wmlprogramming Yahoo group over transcoders? Specifically, the ones that Vodafone UK and other carriers implemented with the goal of making non-mobile web pages more usable on mobile handsets? The issue was that these services had the (hopefully unintended) consequence of degrading or completely breaking numerous mobile web sites and services. Ring tone and game downloads no longer worked, some mobile web sites didn't load or displayed malformed content. Sites that relied on being able to detect mobile browsers and deliver optimized content no longer worked as designed because the transcoders removed or changed the HTTP headers that identified the browser, user's language settings or preferred content types.
Developers and content providers upset with the disruptions to their sites and business models rallied around Luca Passani, co-creator of the WURFL mobile device repository to formulate a document, "Rules for Responsible Reformatting: A Developer Manifesto" which suggested guidelines that transcoders should follow to avoid disrupting existing mobile sites and services. The "Manifesto" was generally well received in the mobile web development community and was also endorsed by three of the major transcoder vendors InfoGin, Volantis and Openwave. Openwave provides the OpenWeb transcoder used by Sprint.
The furor had died down, but now it's been rekindled by the W3C's release of a draft of its "Content Transformation Guidelines" recommendations, which like the Manifesto, describes best practices for mobile transcoders. The Guidelines are open for public comment until Sept 16. Anyone can comment by sending an e-mail to firstname.lastname@example.org (note that your e-mail address will be published on the web - I recommend that you use a disposable e-mail address!). All comments can be viewed at lists.w3.org/Archives/Public/public-bpwg-comments
Their are some clear differences between the two documents. The W3C Guidelines doesn't go as far as the Manifesto in limiting what is acceptable behavior by transcoders, particularly with regard to changing HTTP headers. The Guidelines also place a larger part of the responsibility for interoperability on mobile web developers and publishers rather than transcoder vendors. All of which understandable given that the members of the W3C, including the Mobile Web Best Practices Working Group, are primarily representatives of commercial organizations including mobile carriers, transcoder vendors and large web publishers while the Manifesto comes out of the mobile web developer community.
There are lively discussions about the W3C Guidelines going on both through the comment process and on the wmlprogramming Yahoo group. Luca and others have proposed changes to the Guidelines that would bring it closer to the Manifesto. It remains to be seen if these suggestions will make it into the final document.
In reading both the Guidelines and the Manifesto, I noticed that neither said anything about allowing end-users to opt out of transcoding. I think it is essential that all transcoders offer ordinary users a way to disable the transcoder, either temporarily for the current site or page, or globally for all sites.
In spite of everyone's best intentions, transcoders will sometimes break sites that would otherwise be usable on a given handset. If you have ever used Skweezer, Mowser or the transcoders that Google, Yahoo, AOL and Microsoft Live use to reformat web content returned from search queries, I'm sure you've noticed that some sites come up blank, broken into one line pages or missing essential parts and functionality when transcoded. Fortunately those services are opt-in, no one is forced to use them, and except for Yahoo and AOL, they offer links to the original version. With the carrier transcoders there is often no way to opt out, leaving users no alternative if the transcoded version of one of their favorite sites is broken.
Secure sites pose a special problem for transcoders as they can not be transcoded without decrypting the the secure content, potentially exposing users to "man in the middle" attacks. Users need to be able to opt out of transcoding when doing online banking or shopping when account information or credit car numbers are being passed.
I've left a comment with the W3C arguing for making user opt-out a requirement for all transcoding proxies, I won't bore you by reprinting it here as it essentially restates the above. You can read it in the W3G BPWG archives.
The issue of transcoding, is a very important one for the future of the web on mobile devices. Take a few minutes to skim the Guidelines and the discussions at the W3C and wmlprogramming and if sufficiently motivated, email comments on the W3C Guidelines to email@example.com by the Sept. 16th deadline.