I'm trying to get an idea of all of the effects of applying
position: relative to an element (as opposed to leaving it with the default value
Obviously, the primary effect (laying out the element normally, but then potentially offsetting it via
top, etc.) is explained clearly in the spec -- that part's fine.
position: relative has more effects than simply offsetting the element, because it makes the element "positioned," which has at least these further consequences:
Positioned elements show up in a different place in the stacking order and can have
Positioned elements become offset parents for positioned elements within them
What other effects are there (if any)?
you don't have to offset the element, and if you don't it then becomes handy as a container for absolutely positioned elements, which then take its boundaries as the reference.
it's worth noting that adding position:relative; to create a positioned element fixes certain IE bugs.
you should also note that the z-index of a parent will influence the z-index of a child, so if things aren't stacking as you expect, check what z-index the parent container has.
can't think of any others.