This is a macro that allows you to have arbitrary "help text" as a tooltip for arbitrary text segments.
It depends on browser support, but most will show the title of the span tag wrapped around your text as a tooltip popup. It also changes the cursor and provides a dashed underline, and does it with an inline style rather than require you to add a CSS class.
Syntax example:
[[HelpTitle(displayed text, more information about the displayed text)]]
Only restrictions are that neither the text nor the tooltip can have quotes or commas.