Step 2:

function text_example() {
	return 'Why, this text was just outputted using the shortcode tag you created! Smashing.';
}

Step 3:

add_shortcode('textftw', 'text_example');

Step 4:

function rss_promotion() {
	return '<div class="rsspromot">Never miss a beat - <a href="http://notesblog.com/feed/"> subscribe to the RSS feed!</a></div>';
}

Step 5:

add_shortcode('rsspromo', 'rss_promotion');

Step 6:

div.rsspromo {
	background: #eee;
	border: 1px solid #bbb;
	color: #444;
	font-size: 16px;
	font-style: italic;
}
div.rsspromo a { font-weight:bold; font-style:normal; }