In a report from IDC last month, the analyst firm described how hundreds of tests on pirate software sources showed that more than a third led to Trojans and malicious adware.

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And, of course, if you choose not to pay for such software and pirate it instead, outfits like the Microsoft-backed Business Software Alliance will turn your former employees into tipsters, audit your software use and sue you.

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When the next person signed up, the software would pirate the new address book and spread further.

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Thanks to the advent of affordable pirate-friendly hardware such as CD burners, it's never been easier to make illegal copies of software, movies and music.

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