The Rev Attribute, Link Types, and Vote Links Explained

Rev Attribute

The html rev attribute in my opinion is underused and incredibly useful. In short the rev attribute is the reverse of the rel attribute. Here are the HTML 4.01 specification definitions:

• rel: This attribute describes the relationship from the current document to the anchor specified by the href attribute. The value of this attribute is a space-separated list of link types.
• rev: This attribute is used to describe a reverse link from the anchor specified by the href attribute to the current document. The value of this attribute is a space-separated list of link types.

A few months ago I wrote about the difference between the rev and rel attribute where I give an example which may help, and there is also a good example here.

Link Types

Link types are the values that can be used in the rel and rev attributes. Some link types are old, some are new, some are microformats, others are used by search engine bots. This is the HTML 4.01 list of link types, and this is the HTML 5 draft list of link types.

Some of the link types added to the HTML 5 specification are: archives, author, external, feed, first, and many others. Some of the link types removed are: start, chapter, section, subsection, and a few others.

The external and nofollow link types were also added to the HTML 5 specification which have been widely used for some time now in the rel attribute for SEO purposes. The tag link type was the better defined rel="tag" microformat before it was added to the HTML spec, however I expect and hope the microformat specification will continue. The tag link type was created at Technorati, which they describe here, and this is how it was created.

Vote Links

The Vote Links microformat are rev attribute values that I hope will become a link type in some future HTML specification. These are three values described by the Vote Links microformat, they are:

• vote-for: Represents approval.
• vote-abstain: Represents abstention or indifference.
• vote-against: Represents disapproval.

Currently I always rel="external nofollow" on any link that I will rev="vote-against", and rel="external" any link that I rev="vote-for" atleast once, which covers 75% of my links. But there are other links which I want to be more specific about, and for me that is where the Vote Links microformat comes in handy, because I can vote-for a link that I also nofollow. For example, I usually nofollow my links to Wikipedia (becuase it has so much Page Rank already) and use the vote-for microformat to show my support.

Conclusions

1. The rev attribute has been widely misunderstood and misued, but it is very useful.
2. There is a dramatic difference in the link types defined in the HTML 4 specification and the HTML 5 specification draft, but even some of the depricated link types appear useful to me.
3. The rev attribute is not in the HTML 5 specification draft, which is like removing the yang from a yin-yang, and I have not found a good reason for it, only a few hints which reinforce my belief that it is not good idea.
4. Vote Links rock!
5. Between the HTML specification chaos and Microformats, this is the time where we all get to decide what we want to embrace, and let the HTML specification follow our lead.