[mjb]

> PowerPC has a weakly ordered memory mode

Right, I forgot about PowerPC.

> I think most good high-level programmers know that they need to use high-level locks provided by the SDK, while anyone writing code that actually needs to deal with memory ordering probably already knows to use barriers some of the pitfalls of different ISAs.

Agreed. The point I was trying to make is that, as these platforms become ubiquitous, they'll start attracting the "average" developer more and the "first mover" developers less. I can't prove that "more likely to move onto a new platform" is correlated with "more likely to be aware of threading pitfalls", but I suspect it to be true.