Spivak's talk focuses on operads as a mathematical language for modular systems. Along the way, he asks the interesting question:
> Can you think of a modular environment that is not an operad?
But there is one operad discussed in the talk which is different: Sets.
> it'll be the only operad which doesn't feel modular. ... The mathematical definition goes beyond the motivating intuition.
What are some other significant "non-modular" operads? Was modularity the original motivation behind operads, or is modularity a theme which operads were later found to be well suited for?