What is the benefit to using <acronym> and <abbr>?

Should i give my time to change terms and abbreviations to <acronym> and <abbr>? Is it wort开发者_如何学Goh to use? What are pros to use both tags? Is it useful for SEO and screen reader?

See W3C specs.

An acronym is a kind of abbreviation but not vice versa.

E.g. <acronym lang="en" title="Radio Detection And Ranging">Radar</acronym> or <abbr lang="en" title="Abbreviation">abbr.</abbr>.

There is likely to be no or infinitesimally small SEO benefit from using these tags unless the abbreviation is not well known or something you made up or there is some ambiguity. For example, in an article about LILO the Linux Loader, you may want to specify <acronym title="Linux Loader">LILO</acronym> to avoid confusion with Last In, Last Out.

Any accessibility benefit would exist only for those acronyms and abbreviations that are not well known by the target audience. For instance, it makes very little to no sense to have <abbr lang="en" title="Mister">Mr.</abbr> (WCAG checkpoint 4.2 disagrees with me on this. Note also that I did not provide an expansion of WCAG in my post).

On the other hand, if you use are not using IMF to refer to the International Monetary Fund, it might make sense to use <acronym lang="en" title="Impossible Mission Force">IMF</acronym>.

Now, what happens if you also want to use IMF to mean International Monetary Fund in the same document?

The article The Accessibility Hat Trick: Getting Abbreviations Right might also be useful.

Interesting nuggets:

The assertion that abbr is structural is misguided, as the point of the tag is the content of its title attribute.

...

In [XHTML] version 2, the acronym element has been deprecated, so we're now using the abbr element for all shortened forms.

The first time you use an acronym or an abbreviation in a part of your site, you should mark it with abbr. Here's an example:

I visit <abbr title="Stack Overflow">SO</abbr>, and so should you.

This is useful for a number of reasons:

• Screen readers can read the unabbreviated term
• A user hovering the cursor over that term can see the unabbreviated term
  • This can be coupled with CSS styling to hint that the term is an abbreviation (some browsers do this automatically)
• Search engines are more likely to understand the context of the term

Should you use abbr?

I would recommend using abbr for long-lived documents, such as help pages. Here, clarity is important, and it's worth the extra few minutes peppering your content with abbr tags.

For periodicals like blog posts, you can probably skip abbr. Chances are that if you use an obscure abbreviation, you'll explain it in-text anyway. There's no sense grinding your creative process to a halt by typing HTML tags.

Avoid acronym

If you are going to use acronym or abbr at all though, you may consider using only abbr. Acronyms are a type of abbreviation, and the acronym tag is being dropped in HTML 5.

Before asking "what is the benefit", normally the question you need to answer first is "what is the alternative?"

• CSS tooltips?
• JavaScript tooltips?
• Spelling out the entire word every time?
• Putting the abbreviation in parentheses just once?

The first two put you at risk of the various CSS and JS browser incompatibilities. And the third is going to be pretty irritating for both you and your readers when you have the phrase "National Technology Transfer and Advancement Act" repeated 500 times on the page.

And the last of those... well, it's pretty much the same as using the <ACRONYM> or <ABBR> tag, except using the tags lets the browser decide how to render it (usually with a nice tooltip).

SEO and accessibility... maybe there's some benefit, but I think you should use these tags because they are the right tags, just like <p> is the right tag for a paragraph and <em> is the right tag for emphasized text. Say what you mean!

<acronym> and <abbr> are actually quite useful, precisely for the reasons you mentioned yourself: accessibility and SEO. And it's not that much work, either, because it suffices to mark up only the first occurrence of an acronym or abbreviation on any given page, not all occurrences. In fact, that's precisely what W3C recommends in its accessibility guidelines:

Specify the expansion of each abbreviation or acronym in a document where it first occurs.

Reading the comments on Sinan's answer I think I understand what the question is getting at...

I'd say it completely depends on the circumstances of your text. Using <abbr> tags on everything is pure madness, but you can use it to enhance understanding.

Traditionally, a text that uses abbreviations explains the abbreviation when it's first used. Long names or words can be shortened for the remainder of an article, like so:

The Agency for Awesomeness (AfA) announced [...] An AfA representative said ...

Alternatively, if something is already widely known by its acronym, it is usually briefly clarified the first time it is used like so:

The IMF (International Monetary Fund) has ...

The problem with the web is that you may have a long text split over several pages, and a user can jump to any page without having to read the previous pages. For stylistic purposes you may not want to repeat the definition of every used abbreviation and acronym on every new page. On the other hand, you also don't want to force the user to read your text from the very beginning. This is where the <abbr> and <acronym> tags come in handy. They allow you to (re-)define something without having to break up the flow of the text.

I would add another reason: Style.

One would give more letter-spacing inside an abbr to improve its readability. In the same way, in order to not break the balance of the text, sometimes is preferable to use small caps instead of normal caps.