Those are all great and very interesting examples where senior leaders create a culture by taking tough and visible decisions. I wonder if they worked in the same sort of way that the post describes where new people talk about them and it makes them engage with the issues around the culture? That is, did they have a long-lived effect on culture or were they one-off boosts to it? I think you've got a culture when all employees are reinforcing it rather than just the top leaders.
Actually, I think for half of the examples I mentioned it was rank-and-file Google employees who forged Google's response. I've seen a bunch of examples of regular colleagues galvanizing Google to do the right thing. Often regular Googlers drag execs to the answer we think is right. :)
I think each of the four examples I mentioned did have a long-lasting effect on the company as well, e.g. the Data Liberation Front ( http://www.dataliberation.org/ ) is a natural result of the pledge not to trap users' data.