Remembered this yesterday, and it is such a good litmus test for an idea, from St Seth Godin;

Tell 10 friends who know and trust you your idea then wait to see if they tell anyone else. If they do, you are good to go.

Get skin in the game, go tell 10.

Pierre

PS: If you've bought TRAIN NAKED, and liked it, please rate it on GOODREADS or AMAZON. Would really appreciate it.