1
You might know who your customers are but:
1) Cannot just walk into anyone's office
2) Emails could be as worse as - sent:recieved::100:1
What could be the other channels?
Funnier the better. Just kidding.
I personally think that ideas are more than a dime, unless it's an outright clone. And I am not saying it because of the fear of being cloned or copied; I am rather saying it because discovering/inventing a useful idea is so rare. So it's the scarcity which makes it valuable and not the fact that someone might steal it.
EDIT: Important point missed. The discussion applies more to the people who can implement their ideas on their own.