reply to artisticcheese If it's cracking, it's because it's moving.
I wouldn't worry too terribly about it, as it doesn't appear to have moved much. I don't understand why they created the split in the wall though. It appears that the left and right parts of the wall are only connected by that large (and weak) mortar joint. That created a weak point in the wall.
reply to artisticcheese Looks to be cracked clear through the wall which would be structural failure. Is there steel in there? That mortar joint is too big and the courses should have been staggered throughout the wall. Is there a pvc water sprinkler pipe there? -- Let them eat FIBER!