Yesterday Richard posted a few photographs in which he changed focus during a long exposure. I think many people consider that a type of intentional camera motion, a technique in which one deliberately moves the camera during exposure. I have done very little of it--I lean toward crisp focus, which is the other end of the distribution--but it can be fun. Here is my attempt to create an impressionist view of a water-lily pond in front of the Clark Museum in Williamstown MA. I may have been thinking along those lines because the Clark is home to an exceptional collection of impressionists.
This was done with vertical motion on a ballhead, but one can use any sort of motion. If you search intentional camera motion, you will find some intriguing examples. (Well, I found them intriguing, anyway.)