Every year or two, Ferris Research updates its estimates for the total cost of spam. Here are our 2009 estimates:

Worldwide, spam will cost us all $130 billion; in the U.S. alone, $42 billion. That’s a 30% increase over our 2007 estimates, which themselves were a 100% increase over our 2005 figures.

So the growth in the cost of spam is slowing down. Why do we think that? Here are the three main reasons (most important first):

1. Spam levels aren’t growing (some sources say they’ve declined, but this is as a percentage of total email, but total email volumes have grown, so the two facts roughly cancel out).
2. Spam filters are getting more accurate and more people are using better spam filters (so people need to delete less spam and search for fewer false positives).
3. Spam filters are less expensive than they were (albeit increasingly purchased in a higher-value bundle of other functionality, including archiving/compliance).

The contribution of each cost component to the total is roughly:

• User productivity cost (deleting spam, looking for false positives, etc.): 85%
• Help desk cost (IT helping end users deal with spam): 10%
• Spam control software/hardware/service (licensing fees, amortized capital costs, etc.): 5%

… Richi Jennings