Most of the time, context-level formatting doesn't change the way text is rendered, it just helps to describe the context of the text being used such as addresses, code snippets, and citations. Some context-level tags do apply some sort of effect to the text, but for the most part, it's mainly used to categorize text.

<acronym> </acronym>
Description:	This specifies the text within it is an acronym.
Attributes:	none
Syntax:	<acronym> acronym here </acronym>
Example:	This is W3C recommended HTML.
<address> </address>
Description:	This specifies the text within it is a postal or electronic address.
Attributes:	none
Syntax:	<address> address here </address>
Example:	Our e-mail is html@tucows.com
<cite> </cite>
Description:	This specifies the text within it is the source of a cited passage.
Attributes:	none
Syntax:	<cite> passage source </cite>
Example:	TUCOWS NEWS says making skins is pretty easy.
<code> </code>
Description:	This specifies the text within it is a section of computer code.
Attributes:	none
Syntax:	<code> code here </code>
Example:	printf("Hello World");
<del> </del>
Description:	This specifies the text within it has been deleted. Mainly used for viewing the entire draft of a document.
Attributes:	none
Syntax:	<del> deleted text here </del>
Example:	A U.F.O. crashed in the desert. A weather balloon crashed in the desert.
<dfn> </dfn>
Description:	This specifies the text within it is a definition of a term.
Attributes:	none
Syntax:	<dfn> term and definition here </dfn>
Example:	JavaScript - A web page scripting language.
<em> </em>
Description:	This Specifies text that is to be emphasized.
Attributes:	none
Syntax:	<em> text here </em>
Example:	You must learn HTML.
<ins> </ins>
Description:	This specifies text that has been inserted into an original draft.
Attributes:	none
Syntax:	<ins> new text here </ins>
Example:	The U.F.O. weather balloon was spotted...
<kbd> </kbd>
Description:	This specifies the text within it is keyboard input.
Attributes:	none
Syntax:	<kbd> keyboard input here </kbd>
Example:	Type format B: at the dos prompt.
<q> </q>
Description:	This specifies the text within it is a direct quotation from something.
Attributes:	cite - URL of the quote's online source.
Syntax:	<q cite="URL"> the quote </q>
Example:	"It's Linus' World - We Only Live In It" - Matt Bleicher at TUCOWS NEWS
<samp> </samp>
Description:	This specifies the text within it is actual output from a program.
Attributes:	none
Syntax:	<samp> outputted text </samp>
Example:	This should print out Hello World!.
<strong> </strong>
Description:	This specifies the text within it is strongly emphasized.
Attributes:	none
Syntax:	<strong> strongly emphasized text </strong>
Example:	You must remember to breathe!
<var> </var>
Description:	This specifies the text within it is a variable in a computer program.
Attributes:	none
Syntax:	<var> variable name </var>
Example:	Look out for the foo variable.

     Remember, context-level tags are mainly for describing the context you wish the text to be in, whether it be an address, citation or program variable. These do come in handy when you're working with technical or very textual documents.