I have spent some time to organize my Accounts (customers) into relevant categories (using Industry field) + I spend great deal of time to add contacts to those accounts. Now I need to send an email to several customers (Accounts) in certain category. Can not find a way to do it. No email option in Campaigns, no such thing in Accounts. How I am supposed to communicate with my existing customers? 

Am I missing a point about purpose of CRM?