Theresa Neil at Designing Web Interfaces – iTunes Solves the Nested Clause Dilema:

"Now, to my delight, Apple has tackled the last remaining frontier of predicate editors- the nested clause. My design partner, Jessica, found this when trying to pull together a playlist for her birthday last week. She needed something more complex than a simple AND or OR (which Apple eloquently rephrased as “matching all of these conditions” or “matching any of these conditions”)."