I knew a Datacenter that had hundreds of ps3s for rendering fluid simulation and other such things that at the time were absolutely cutting edge tech. I believe F1 and some early 3d pixar stuff was rendered on those farms. But like all things, technology marched on. fpgpas and cuda have taken that space.

Cell definitely was heavily used by specialist/nichr industry though.

I wonder if I can find you some link to explain it better than the rumours I heard from staff that used to work in those datacentres.

Hmm hard to find commercial applications, probably individuals might have blogged otherwise here's what I'm talking about: https://en.m.wikipedia.org/wiki/PlayStation_3_cluster