There's a ridiculous rumor running around the net that Linux is so inherently secure -- or so securely obscure -- that you shouldn't even bother running an antivirus on it. But frankly, that's just not true. While it is true that there are very few significant viruses that target Linux today, the plain fact is that these threats do exist, and they're far more likely to infect an unprotected PC than one that's running an antivirus app.