I have been using Windows 8 for a while, and I have just remembered that I did not install any antivirus software. To my surprise, I don't think Windows 8 has ever shown any of the usual nag popups that appeared in Windows 7, Vista, or XP if you didn't keep an up-to-date antivirus.
Is there a default antivirus in Windows 8 already installed? Or is the nag popup just disabled?