One of HTML5′s structural tags is aside. I must admit to liking this one as soon as I found out about it; it seemed to promise a way of adding a little writerliness to blog posts, even a little depth. On a practical level, it could help authors supply supplementary or tangential information within their documents. One of the best uses of asides (not the actual tag itself) can be found on Jon Tan’s site:
A brief aside from Jon Tan's website
At least that’s what I thought an aside was. And the dictionary agrees with me:
a temporary departure from a main theme or topic, esp. a parenthetical comment or remark; short digression Dictionary.com
However. Here’s the HTML5 spec:
The aside element represents a section of a page that consists of content that is tangentially related to the content around the aside element, and which could be considered separate from that content. Such sections are often represented as sidebars in printed typography.
The element can be used for typographical effects like pull quotes or sidebars, for advertising, for groups of nav elements, and for other content that is considered separate from the main content of the page.
It’s not appropriate to use the aside element just for parentheticals, since those are part of the main flow of the document. HTML5 specification
The problem here is that the spec stretches the natural interpretation of what an aside is, i.e. a short, temporary digression. Blogrolls and other side content on a blog
are not short or temporary, or even necessarily tangentially related to the main content.
An aside is a conversational digression, and belongs solely within an article or section tag, not independent of it. Without a surrounding article or section there’s nothing to digress from.
A sidebar could easily be represented by an, erm, sidebar tag. If we allow equally presentational tags such as header and footer, then it makes no sense to disallow sidebar. All of these tags serve a semantic function, even if their names are rooted in their appearance on the page (especially when they’re so prevalent on web pages). A sidebar simply serves as a container for content outside of the main article.
One use of a sidebar in The Guardian. Note that the sidebar could contain content unrelated to the main story, such as adverts or a table of contents
For me this represents a problem with HTML5. The meaning of most HTML 4 tags is not really open to interpretation, so it’s pretty easy to start marking up documents with just a list of tags. When a tag’s purpose is not self-evident (from its natural language meaning), or the reasoning behind the naming and usage of tags is inconsistent, then this will cause problems.