- Written by Chris Hirst
There is a common misconception especially in the SEO community over some components used in HTML documents, the most common one being the alt attributes of the image element. It is all too often referred to incorrectly, as an alt "tag". This mis-information has spread and perpetuated, due in no small part to the proliferation of SEOs who have very little or no experience at all with the technicalities of HTML or website / webpage design.
So to try and redress the balance a little, we have a short tutorial / reference to what each item is.
Elements and Tags
tags are the start and end delimiters of HTML elements. A start tag would look like this: <title> and an end tag for the same element would be exactly the same, only with a forward slash "/" before the element name. so it would be </title>
The majority of HTML elements consist of a start tag and an end tag with the content of the element located in-between them. Such as:-
<title>This would be the page title</title>
Some elements do not have a corresponding end tag and are known as "self-closing elements". These are element that do not have a separate content part, rather the content that is displayed or indicated by the element is referenced in an attribute. The self closing element most used in webpage design is probably the image element.
alt and title attributes
Here is where much confusion has been created. The alt attribute of the image element is of particular interest to anyone looking to optimise their pages for search.
The attribute exists to provide alternate text to be displayed in user agents that not enabled with image rendering capabilities.
As search engine indexers cannot "read" or "see" images, the content of the alt attribute, the alt text, is used to determine the context of the image OR, if the image is used as a link the alt text is used as the anchor text. For the SEs where anchor text is used to reinforce the target page content, this is an important point.
BUT it is NOT a tag it is an attribute.
As with all visible HTML elements, the image element has a "title" attribute which has absolutely no use for search but should NOT be confused with the title element, which is possibly the most important element on the page.
<img src='image_path' alt='This is the alternate text' title='This is the title text' >
nofollow is a means that has been developed by the three major Internet search engines where webmasters can show that an external link is NOT vouched for by the site owner and should not be used by the SEs to give value or weight to the target site. However, the implementation of the nofollow differs between the various engine, so it should NOT be taken as an absolute that applying a nofollow to external links will safeguard a page from incurring whatever "penalties" exist for linking to pages that are regarded as "bad neighbourhoods" by the SEs.
The nofollow is NOT a tag and it is NOT an attribute. It is a value that can be applied to the rel attribute of anchor elements. This attribute is used to indicate a relationship for the anchor or link element to the resource indicated in the href attribute, as used for external style sheets, (rel="stylesheet")
<a href='target_url' title='Some title text' rel='nofollow'>Anchor Text</a>
Accessibility and Usability
While on the subject of alt and title attributes, it is worth noting that both of these attributes are useful for website accessibility for different reasons. So please DO NOT "stuff" these important attributes with "keywords" purely for the dubious search engine benefit.
You'll find more on how NOT to use these attributes at the RNIB Web Access Centre blog in the article on Too much accessibility - TITLE attributes