They make "glacial" speed look like an avalanche.
Actually, they still move along at a pretty good clip, but it takes millions of years to see the changes.
The most recent significant changes have been the raising of the Isthmus of Panama, and the continuing collision of India with the Asian Plate. These two things caused massive changes in global ocean and atmospheric circulation.
I can imagine so, altering ocean currents, and geothermal effects.
Actually, the plate shifting is a little more rapid than people think. The Himalayas are "growing" at an amazing 1/2" a year.
Pretty awesome, in my book.