On: 5 Lesser Used HTML Elements

The <del> and <ins> elements are interesting. I fail to see how they are different from the <strike> and <u> elements that existed in HTML 4. To me the result looks like same[1], perhaps it more for semantic reasons?

[1] - http://jsfiddle.net/9h6s7zz3/

They are indeed different for semantic reasons. The <del> and <ins> elements are used to represent edits to the document [1] while <u> is used to "label" names or misspelt text. [2] The <strike> element doesn't exist anymore but was used for styling text [3], much like CSS.

[1]: http://www.w3.org/TR/html5/edits.html

[2]: http://www.w3.org/TR/html5/text-level-semantics.html#the-u-e...

[3]: http://www.w3.org/TR/html4/present/graphics.html#h-15.2.1

It's probably the same difference as <b> vs. <strong> and <i> vs. <em>, so yes, sematic reasons

http://stackoverflow.com/questions/271743/whats-the-differen...

ins and del also define extended semantics attribute (@datetime and @cite), though I don't know that any browser does anything with them.

Browsers aren't the only tools for working with web content.

They're not new in HTML5, they existed in the HTML4 specification: http://www.w3.org/TR/html401/struct/text.html#h-9.4

And yes, the justification is purely for semantic markup reasons.