Inline elements:
respect left & right margins and padding, but not top & bottom
cannot have a width and height set
allow other elements to sit to their left and right.
see very important side notes on this here.
Block elements:
respect all of those
force a line break after the block element
acquires full-width if width not defined
Inline-block elements:
allow other elements to sit to their left and right
respect top & bottom margins and padding
respect height and width