address should be used specifically for the contact details relating either to the entire web page (and so only used once) or to an
article element (see Sectioning). It’s isn’t, as it might at first appear, for marking up any old address willy-nilly.
<h3>Author contact details</h3> <address> <ul> <li>0123-456-7890</li> <li>firstname.lastname@example.org</li> <li>http://www.noplaceinteresting.com/contactme/</li> </ul> </address>
dfn is a definition term and is used to highlight the first use of a term. Like
title attribute can be used to describe the term.
<p>Bob's <dfn title="Dog">canine</dfn> mother and <dfn title="Horse">equine</dfn> father sat him down and carefully explained that he was an <dfn title="A mutation that combines two or more sets of chromosomes from different species">allopolyploid</dfn> organism.</p>
bdo can be used to reverse the direction of the text, and can be used to display languages that read right to left. The value of the required attribute
dir can be
ltr (left to right) or
rtl (right to left).
<bdo dir="rtl">god lmth</bdo>
del are used to display editorial insertions and deletions respectively. Strictly speaking, they aren’t limited to text and can be used over whole swathes of content but, typically, they are used in moderation just like “Track Changes” feature in word processors tend to be.
They can have the attributes
datetime to indicate when the edit was made and
cite, to point to a description as to why the edit has been made.
<p>I have decided to <del datetime="2013-01-26">decrease</del> <ins cite="http://www.icecreamforall.com/changeofpolicy/">increase</ins> the amount of free ice cream that the State will provide for its citizens.</p>