Sgt_Kickaxe - 5:27 am on Jun 13, 2012 (gmt 0)
Don't forget about the search smartness feature in which your pages are ranked according to what level of education is required to read them. I'm sure spelling mistakes would be a sign 'you no seam 2 be 2 smart nohow' but who knows if it impacts actual serps.
My knee-jerk reaction is to say "Google feels you shouldn't make them". I'd agree with that.