Every once in a while you come across something you thought was common knowledge and discover someone who hasn't seen it.
Here is my example.
There are a few fields that were added back in Domino 7 that people may not be aware of...
$$HTMLFrontMatter allows you to add a custom doctype declaration to a form. Quite handy if your designer developed for something other than HTML 4.01 Transitional.
$$HTMLTagAttributes allows you to add your own options to the HTML tag.