There are several things that affect Image quality and I have found that given the same image, people will each see differant problems (or none) at varioues levels. There is also the display technology. A 60" plasma will show a hell of a lot more PQ problems than the same signal sent to a 42" DLP, or even an older CRT projection TV.
We all need to consider the display type when trying to talk to each other.
IMO, Pixulation does not exist unless you have a low signal level or some other error.
I beleive the image quality problems we all see, and contribute to overcompression, is due to a reduction in the Forward Error Correction (FEC) componenet of the signal. This is what makes the image less than perfect. Loss data trying to be filled in by the tuner. I guess that is a form of pixulation, but what actually IS the technical discription of pixulation.
Perhaps the commpression issue could be called micro-pixulation.
Maybe we need to develop a library of images that match terminolgy. It sure would go a long way to help us explain problems.