Some time ago I moaned that Firefox does not have a navigation toolbar that its predecessor Mozilla once did. Link support seems to be implemented within an extension/plugin/addon, whatever. Still that’s not going to aid adoption for “link” aided navigation.
AFAIK IE doesn’t implement link navigation at all and Opera does have some some support hidden away in the menu. Reason why I say some, is because link rel=‘archives’ is currently heavily used on this blog and unfortunately that particular relationship is not supported in Opera. I don’t think link rel is supported on Webkit or any mobile UA I’ve played with. So I think I’ll probably do away with the link elements on my blog to save some precious bytes.
I’ve liked the “link toolbar”, however it doesn’t seem to have taken off. I thought it could be an aid for accessibility, but I don’t think the WAI people have jumped on this. I wonder if Google (or other search engines) uses link rel to help crawl the site. Otherwise, I guess link rel as a navigation aid will be just one of those things… like accesskeys. Actually I like the Search Keys extension as links are automatically numbered. I’ve wanted something like that for my mobile UA for years.
Web authors should write less and UAs do more, so we probably can do away with link navigation and accesskeys to an extent.