This is obviously my personal oppinion by why is it the larger a company is, their logos seem to be really boring. Case in point facebook, google, zynga, tesco. I of course see the argument that they are SO big they have to A.play it safe and B.be extremly legable, usable memerable ect ect.
They go to top creative agencies to develop there identity but they can often seem like a combination of clip art and MS word.
A safe logo ticking all the usability boxs does have to be boring or ugly. So why time and time again do they end up like this.