Brian Zmijewski was an unknown name to me before Mozcon 2011. When he took to the stage however, his content blew everyone away. Brian talked on many different examples that he has seen and experienced. What surprised me was at the end when he said that they do not do much A/B and/or multivariate testing. This may be all well and good for large brands, but you have to be careful of this especially on the Mom and Pop Shop level.
Here is his Storify: