Sustaining Digital Certificate Security
It makes me* uncomfortable that Google has effectively appointed themselves as the internet police and using their power to push people around like this.  But at the same time, there is nobody else (?) who is taking care of this, and I suppose the good of someone/anyone looking into and taking action on the sorts of serious problems that Symantec has exhibited probably outweighs my discomfort.* Disclaimer: Google employee, no connection to any of this cert stuff.