filter's display value

Ok, I know filters are not part of the spec but I have a couple of questions.

What is a filter's display value? They don't seem to occupy any space. For example, the
shadow filter will be visible in the area of it's container element (applying the filter to
an image while the image is in a TD) but will not try to push it's way to be 100% visible.

And my other question: Are filters going to be part of a spec? Or maybe any equivalents?

Please do not refer to SVG... I decided it's not time to use them as a standard yet (anyone
has statistics on Adobe SVG plugging usage?).

Thanks for your time.

Regards,
Manos