In this respect - be especially aware of disgruntled sales and marketing staff, in case they take their bad feelings out on you. One security technique that works is to seed customer lists with dummy customers . Any unauthorised contact with these dummy customers will come straight to you - and you can then identify the source. This technique is used by list rental firms. That is how they know that you have re-used a list when you only paid for a single use.
Employees normally know what is going on in a company.
They also know when things are going badly. Yet many firms keep quiet - refusing to warn staff about problems until too late. Believe it or not - openness with staff is often a safer approach . Let them know how the company is doing - and if things are going badly, how you plan to improve things. Keeping them in the dark only starts rumours - and dissatisfaction.