measuring coolwhip

I would measure one cup unless the recipe specified an 8oz container...

(granted I cook in Kansas, not Paris)

theres a poem, 8oz is a half pint, the world around.

That's a good question - because a whole (regular size) container of cool whip probably only weighs about 8 oz - but there's a lot more than one cup in there by volume. I would add one cup - because Rockhead's right - if they wanted the whole container they'd have specified what size.

I....have heard this....

You have hit upon one of the infelicities of the American system of measures: a "cup" is both a measure of weight and a measure of volume. For liquids, a "cup" is a measure of weight (equal to eight ounces); for solids, it's a measure of volume. For the most part, it's clear from the context what type of "cup" is meant, but occasionally there is an ambiguity. In this case, one must ask: is Cool Whip more like a liquid or a solid? That's a philosophical conundrum that has baffled mankind for centuries.

Finally, take note of the correct pronunciation of "Cool Whip:"