A sockpuppet is someone who uses multiple accounts in order to misbehave online (troll, vandalise, game the system etc). Mainly used on Wikipedia. The "puppet master" or sockpuppeteer controls various "puppets", who work together to meet the demands of the miscreant.
I may as well come out and say that I am snow4sydney (and briefly Brad_Nuker). I changed my handle to better reflect my location, namely, because I'm exposed to the south. Nothing more. Hence, the sockpuppet thing is a bit of fun