A roadside sign for a gas station against a bright blue sky

When they are aware of it, developers often use the <address> tag to surround contact information for a business or individual on their site. Until very recently, this was technically incorrect: the <address> element was intended to markup the contact information for the person responsible for the site.

Photograph of a magnifying glass zooming text

In the original HTML 3.2 spec, <small> was a purely presentational element, the opposite to <big>: collectively, the tags literally made text smaller and larger.

Quite correctly, <big> was dropped from the HTML5 specification - its effect can be easily replicated by using font-size in CSS - but <small> was retained, and redefined to have a purpose.

Historically, many different technologies have been used to create accordion menus and “show more” interfaces on web pages. HTML tosses its hat into the ring with the details and <summary> elements. At their simplest, the new tags look something like this: