What Does REL Mean?
Part of the code for a link may include a ‘rel’ signifier, which is short for relation. It tells a WebCrawler something about the link, and is used to fine tune certain aspects of SEO. There are two terms frequently used by us:
What are rel attributes?
Rel attributes pertain to links and describe the relationship of the linked target to the current. Links are a very strong contributing component to all major web search engine algorithms and within that there are many data properties and qualities pertaining to the links that point to a document, that are under consideration. In that way rel attributes assist search engines in getting additional meaning from those links attributed. Let’s examine which ones you need to know about; which ones solve common webmaster problems, and which are more valuable in the meaning they give to search engines.
Need to know rel attributes
First out of the starter gates is rel=nofollow, which is actually a bit of a misnomer as it doesn’t always mean a search engine will not follow a link but is more of a concern from an SEO perspective as this attribute prevents the flow of equity/authority from the linking page to that linked target; such equity being PageRank which is a Google algorithm. If you’re unfamiliar with PageRank then this video by Google head of webspam is a good place to start.
It’s perfectly reasonable to wonder why we might need such an attribute as doesn’t this seem counter-intuitive to the spirit of the web and link-based ranking? Perhaps so, but like most rel attributes rel=nofollow was introduced to solve a problem or at least disincentive a practice that was becoming problematic; that being the issue of comment spam.
You can use rel=nofollow when linking to sites that you may not trust, or perhaps if you have comment functionality on your blog you could consider setting this as a preference to discourage comment spam and because you can’t really legislate for the quality and validity of the sites of commenters. Indeed, some blog platforms may have this as a default setting when comment facilities are on. It is your choice as a webmaster though if you choose to use this!
One situation that you would be wise to be aware of and consider the use of rel=nofollow is in commercial content that contains a link to any of your documents. According to Google guidelines paid links should use the rel=nofollow attribute to prevent the flow of PageRank. Whilst it’s not my place to police the internet I’d advise anyone to be aware of the major search engines’ stance on paid links and how the nofollow attribute should be used.
Problem Solving Rel Attributes
In 2009 the big three search engines announced support for this tag which solves a common problem for many webmasters and for search engines trying to “treat” this problem accordingly and that problem being duplicate or substantially similar content.
Duplicate or substantially similar content is a problem for search engines in that:
- It’s hard to work out the intended “original” or authority source
- Can lead to unnecessary pages (and use of resource) in the index
It’s a problem for webmasters in that:
- It can lead to equity dilution if other sites link to duplicated pages
- It can mean that your pages are not getting indexed if a search engine thinks they are the same/not offering enough differentiation to warrant indexing
- It can be a huge waste of crawl budget say if for example your CMS generates query URLs
- It can cause ranking issues if a query or otherwise duplicate but peripheral URL (e.g. paginated URL) usurps the preferred target page
However duplicate or substantially similar URLs can occur for all kinds of common reasons such as:
- Legacy build, migration of otherwise CMS issues can often lead to you having multiple versions of a home URL e.g. http://anysite.com versus http://anysite.com/html
- Query URLs or URLs that contain appended parameters that might track (for example) how a visitor has arrived at a site
- Ecommerce sites may carry many, many versions of products that differ just a tiny bit from page to page e.g. 10mm wood screws, versus 12 mm wood screws
The canonical tag allows you to tell the search engines which of the set is the intended; the preferred above all others, however it can cause a lot of harm if implemented incorrectly or used to treat symptoms when perhaps another solution would treat cause.
In something of a follow-on from the previous; rel=prev (or rel=next) are perfect for paginated component URLs and help solve the duplicate (or substantially similar) content issues that can arise from pagination issues. I don’t want to re-invent the wheel here as we already have a fantastic post on State of Search which rounds up some of the leading experts speaking about this issue, usage of rel=prev and next and how this interplay’s with rel=canonical, so I’m simply going to tell you that you must read this piece.
Can be used to link to an alternate version such as a printer friendly page, however more topical and useful for international SEO is using rel=alternate in conjunction with hreflang.
Using this markup, you can tell Google that you know there are multiple versions of what is mostly the same page BUT are targeting different countries. Either because they are in different languages or the same language but with slight colloquial differences e.g. American English or that there are functional differences such as currency and payment method. Essentially the pages may look the same or substantially similar but there is a good reason both should be indexed and shown to their intended and geographic market.
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