Samples

Here are some more or less simple samples I could think of... feel free to modify them to fit your needs.
(To use those, you need to import samples_export)

samples
nameoutputcode
htmltext <html><br/> {htmltext}
<html><br/>
{/htmltext}
html:decode
(the opposite of htmltext)
bold {html:decode}
<b>bold</b>
{/html:decode}
replace
from, to
i don't have a cat. {replace from="dog" to="cat"}
i don't have a dog.
{/replace}
keywordhilight
keyword, class
this keyword is important. {keywordhilight keyword="keyword" class="sectiontableheader"}
this keyword is important.
{/keywordhilight}
linkifykeywords
keywords, urls - both '|'-separated

Note: you could add the parameters as arguments and set the "Activation" to "Every Content", this way it would apply to every content automatically.
Joomla is a PHP-based CMS. test: Joomla is a PHP-based CMS which looks like Java Java. So, the three parts of "Joomla", "Java", and "PHP" are important tools. {linkifykeywords keywords="PHP|Joomla|CMS" urls="http://www.php.net/|
http://www.joomla.org/|
http://en.wikipedia.org/wiki/Content_management_system"}
Joomla is a PHP-based CMS.
{/linkifykeywords}
linkifytext
Moslate is also hosted at http://developer.joomla.org/sf/projects/moslate {linkifytext}
Moslate is also hosted at http://developer.joomla.org/sf/projects/moslate
{/linkifytext}
scriptlet

Note: make sure you set the access level for the creator appropriate.
I do not encourage to use this tag, but if you feel you really have to - here you are.
Hello World! {scriptlet}
echo "Hello World!";
{/scriptlet}