Just a quick thought – courtesy of my chum Alex.
When we think about how ideas or behaviours spread through a particular population, we naturally tend to focus only on "our" thing – the idea or behaviour that we want folk to adopt. We talk about the thing's stickiness, we think about adoption only in terms of what matters to us – as a yes/no thing. This is all understandable as the thing that matters is the thing that matters to us.
The point is that this thinking is at the expense of all the other things that are spreading through that population at the same time that aren't so important to us. As we live in a social soup, with ever greater degrees of connectedness, this just seems the wrong way to think about spread.
Rather than it being like tossing a pebble on a pond and waiting to watch the ripples spread, it's really more useful to think of things like this: a paddling pool with lots of noisy kids, splashing around. As Tom Stoppard put it in Arcadia, "it's really hard to hear the tune".
Let's have a look at how a number of things seem to spread rather than just ours (this might tell us something useful about how to help ours spread faster/further)
Oh, and let's try a bit more humility – less "stickiness", more slippiness, maybe? More what the kids in the pool find interesting/refreshing than what we do to them ?
BTW can anyone remember the smell of those plastic paddling pools? All hot and grassy?