What a smooth picture like that!!
The "untouched" picture you linked to is not untouched, the crazy noise has been added afterwards. If you look at the DPReview gallery for DP2, which should have more noise, you can see that the pictures look fine even at ISO800, see
The look in those pictures can be achieved with aggressive noise reduction, and resizing the images smaller. They also have extreme high key and desaturated processing to enhance the look. (Google "high key" if you're not familiar.)
|AT-6 Harvard by jarud|
from Trainer aircraft
|Monarch butterflies winter roost at Pismo Beach by cjf2|
from Safety in Numbers (Nature)