Contest: The secret for spreading ideas? (prize: signed copy)

As part of the countdown to Myths of Innovation day (Oct 13th - sign-up here), we're running trivia and other contests, with some fun and unusual prizes.  Some questions require looking at the free sample chapters found here (PDF).

The Prize:  A signed copy of the new paperback edition of Myths of Innovation.

Rules: anyone enters by leaving a comment – one winner will be chosen at random from correct entries.  I'm  the final arbiter of rules, including rulings about rules or rule like sub-rules, slide-rules, slides of all kinds, laws, by-laws, in-laws, laws about common law rules regarding the application of contest laws and sub-law rulings.

Ready? Here we go:

Some have complained the questions are to easy. Ok – try this one.

Question: Which of Rogers factors in Innovation diffusion is the hardest for an inventor to overcome? and why? (see chp 4 in the free sample)?