Spam Costs... You pay phone charges when you download it, it delays receipt of real email, you spend time scanning & deleting it, and in extreme cases you may miss legitimate emails within a morass of unwanted advertising. As an employer, you could even be held liable if your employees are regularly subjected to material that they find distressing or objectionable.
For a small Business with 10 employees, on an average salary of €30,000, each spending ten minutes a day checking and deleting spam, the cost in lost productivity is over €7,000 per year.