Ever wondered why after so many years, despite CanSpam laws and improved email filters, the volume of spam continues to rise? The answer is quite simple: because it works. At least according to Internet security firm Marshal, which recently released a study that claims 29.1% of web users make purchases as a result of email spam.

The most common items purchased, says the report, are sexual enhancement pills, software, adult material and luxury items such as jewelry and clothing - most of which is either pirated material or brand name knock-offs. For comparison's sake, it's worth noting that Forrester Research conducted a similar poll four years ago and discovered that 20% had made purchases from spam, so the number appears to be growing.

The rate at which this problem is growing may seem unbelievable, with the volume of unsolicited email supposedly having doubled since last year, and even more so the fact that people are actually bothering to read these emails. But as long as there are those willing to buy, spam emails will keep on coming.