Navigation based on <link> elements

This doesn't qualify as a "must have" feature, but personally I'd like to see  navigation support via <link> elements natively supported in PunBB 1.3.

<link> elements allow a UA to map keyboard shortcuts to limited set of predefined navigation actions. The ones that I've found useful are: "home", "copyright", "author", "first", "up", "last", "prev", and "next". An example would be <link rel="next" href="?id=23&p=2">.

The accesskey attributes used by PunBB 1.2x have the drawback that if supported the keys are likely to be specific to that one site (one type of forum software in the case of PunBB), they are likely to interfere with a UAs native keyboard shortcuts, and there are very few shortcuts that can be considered safe for use if an author wants to avoid clashing with the native keyboard shortcuts defined in the various browsers. This is why the accesskey attribute is widely considered as harmful to accessibility. A <link> based navigation system doesn't have any of these drawbacks.

For most sites it is difficult to argue the practical usefulness of inserting a <link> based navigation system. IE has no support for it, and most people who use UAs that do support it will not be aware that a site offers such a system due to their browser being configured not to show the <link> navbar. Web discussion forums are IMO an exeption, many users use a certain forum site often. The site's forum introduction message and "Help" section could point out such a feature, explain the benefit, how to use it and what browser's have support for this feature. It brings Web based forum/application a step closer to the facilities offered by a local application.

Opera has some keyboard shortcuts pre-assigned to certain <link> actions (four from the above mentioned set in Opera 8.x, two in Opera 9), more can be configured by the user IIRC. Mozilla Suite/Seamonkey has native support for <link> based navigation, AFAIK there are extensions for Firefox. I haven't checked on the current level of support for coupling keyboard shortcuts to <link> actions in the Mozilla family of browsers. I don't know about the support in other browsers.

The link elements would have to be generated programatically, AFAICS this should be easy to do and not require any significant resources.

One example of a useful purpose would be to enable users to use the keyboard to navigate to the next page in a multi page message thread or multi page index. Or use the mouse via the <link> navbar that Opera and Seamonkey have. It may also be possible to use client side Javascript to dynamically redefine the action of for example a "Next" link to move to the next message instead of the next page if a user has used a fragment identifier link to bring a particular message in a thread to the top (by checking the address in the address bar for the presence of the fragment ID).

Apart from enabling keyboard navigation there is also the advantage of bringing structure to a site which otherwise is only a collection of pages to for example search engines. For example the pages of a paginated discussion thread can be linked together. I doubt if any SE actually makes use of this information, so on this aspect there are probably currently no practical advantages from doing this.