Here's a nice news story:
Security experts predict the total number of viruses will reach one million by the end of the year, as malware writers create new types of exploits to combat the improved security policies of businesses and consumers.
But there's something missing in this paragraph – and, indeed, in the whole story: it's the word “Windows”. This is the dirty secret behind viruses: they are overwhelmingly found on Windows systems. The huge, global cost of viruses is just one of the hidden extra fees that we all, collectively, must pay when others use Microsoft Windows. Pity Microsoft doesn't use some of its extensive cash holdings to compensate victims of its poor coding.
Now, of course, if all the world used GNU/Linux, that wouldn't mean that viruses would cease to exist: the focus of malware would shift, and viruses would become more common for that system too. But you can bet they'd be far harder to write, and that there would be far less than a million.