I was playing around with the new /setblock command in 13w37a.

What I expected to happen was:
The block would appear/replace the block at the right coordinates.
What actually happened was:
The block would appear next to the coordinates I typed in, and not on the exact spot. I did use the coordinates in the (), (e.g.: x=7.123 (7) ), but it still placed the block one spot away from the specified target.