rel, rev, and HTML5

Here’s the conclusion that all the web gurus seem to have drawn over the past months: HTML5 is the future, and that future is slowly creeping into our midst. This article by Dave Shea is the latest proof of that. Then there are inspiration galleries and blogs dedicated to the use of HTML5 for markup, plus hardly any mention of XHTML2 anywhere else.

rel and more meaningful links

But I’m not going to get into the war between the two here; I’ll just focus on a specific development in the arena: link relations. There’s more to it than rel=stylesheet and rel=alternate. About a dozen more.

For example, the Google-imposed rel=nofollow will be officially added in HTML5, but the seemingly convenient rel=feed may be dropped due to browser implementation. Other interesting link relations mentioned are rel=search, which obviously points to a search page, and rel=sidebar, which refers to a document “shown in a secondary browsing context (if possible), instead of in the current browsing context.” More are being proposed here, including rel=accessiblity.

rel seems to be what plugins are to web browsers, so it’s interesting to see how they can make a markup language as extensible as possible.

rev and a less rotten web

Still related to link relations is the rev attribute, which stands for a “reverse link”. It hasn’t been as popular as its cousin rel up until microblogging boomed, and consequently, URL shorteners and the threat of link rot.

Considering just how popular Twitter is these days, particularly as a social media marketing and SEO tool where links are the mode of currency, using rev=canonical to indicate one URL is a shortened version of the other:

Google introduced rel="canonical" recently. It’s a way of pointing from an alternate URL back to the canonical URL of the current document: the relationship of the linked document to the current document is “canonical”.

If you’re linking from the canonical URL to an alternate URL (like, say, a shortened URL), you could use rev=”canonical”: the relationship of the current document to the linked document is “canonical”.

People are also advised to check long URLs at this RevCanonical app to determine whether they already contain shortened ones.