My friend, colleague and futurist Paul Saffo coined the quip “strong opinions weakly held” sometime in the mid to late 2000s (at least that is when I first heard about it). Paul writes about the concept on his blog.
I always like the idea – but also think that it is being used as a justification for people to do the first part (“strong opinions”) without actually buying into the concept of the second part (“weakly held). Which is, of course, the exact opposite of what Paul intended to achieve.