Allows to define shortcodes for easy replacement. Handy for recurrent copy/paste’s from sites like YouTube or DailyMotion… But not only. You decide! Also allows you not to write un-valid tags that would be stripped out by WordPress (<object>s for example)
The syntaxt is Shortcodes’ one, but for legacy reasons you can use this syntax : [key:parameter1,parameter2,parameter3…]