VERY good question dn! Of course the first starting point is the security you have if you are connecting to a wireless network (rather hardwire your Wii via the USB via Cat 5 or similar cable) . I've read with alarm some threads where folks have removed the password from their wireless network to overcome internet connectivity issues - which typically manifest as a 51330 error. Then there is the security settings in your router. I've not heard of any hack, DOS attack, spyware, worm hits on Wiis - but that doesn't mean it doesn't happen. One would hope that any Nintendo hosted web content is secured by SSL (https) encryption.