n. The source of anything presented as fact that sounds unverified, unbelievable or otherwise devoid of fact.
Adj. Anyone who over-quotes internet based "knowledge exchanges", like Wikipedia, Wikianswers, Answers.com, etc.
Son: Dad, Tiësto is bigger than Elvis!
Dad: Where'd you pull that from, your Wikiass?
Guy #1: Dude, Steve Jobs was the greatest inventor-genius of all time. He's been cited as primary or co-inventor on 241 patents in the US Patent Office.
Guy #2: How do you even know that?
Guy #1: Answers.com! And did you know Steve Wozniak is worth about $6.2 Billion?
Guy #3 (under his breath): What a Wikiass.