Valleywag has an excellent Cheatsheet on What is Digg? Basically, if someone asks you what is Digg, just send them there. It describes the basics, how it works, how to break it, Digg's competitors, the recent publicity on Digg, "How Digg fits the buzzwords," oh and don't say "I got digged," I believe it is "I was dugg." Full details on Digg at Valleywag.
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