Expression or the anticipation of expression?

The Slides.JPG
Originally uploaded by alt.planning.

What is art in a commercial context? The Tate Modern was absolutely heaving, which is great, slides are a great thing, but are they art?

There's a lovely story about Leo Burnett in Sydney who kept inflated the emergency evacuation slide in the building's atrium, just for the fun of it. Good for them.

Should advertising be more arty or more fun - or are they not mutually exclusive concepts?