Elmore Leonard said that "Keep your exclamation points under control. You are allowed no more than two or three per 100,000 words of prose. If you have a knack of playing with exclaimers the way Tom Wolfe does, you can throw them in by the handful."
It is amazing to me that I can make significant judgements about a person who seems to have such an extreme view.
I often read also that in the business world, the usage of exclamation marks is decidedly unprofessional, something which I don't particularly agree with but I suppose you generally have to live with the system.