In terms of cost per head of population, spam costs US business $59 per person, while in Japan the cost is $41, in Germany $55 and in the UK $42 (about £22).
Much of the cost is in lost employee productivity, according to the report. Not included in the figures are immeasurable items, such as the missed "opportunity cost" of a new customer order that's incorrectly discarded as spam.
The San Francisco-based researchers also found that organisations can minimise the loss of productivity by deploying an accurate anti-spam system. Systems that have a very low false positive rating – which relates to the number of legitimate e-mails filtered out as spam – are needed to drive costs down further.
However, the company warned that desktop-based anti-spam tools often have a lower return on investment than server-based tools – a result of higher purchase costs and ongoing maintenance and helpdesk costs.
Desktop filtering may in some circumstances be more expensive than manual filtering, where the employee simply deletes the spam himself, says the report.
