I thought this article did a decent job of examining what's going on with G's answer box. I like the way the guy scooped up the expired domain that was in his examle.
http://cognitiveseo.com/blog/6266/decoding-google-answer-box-algorithm-serp-research-10-353-keywords/
Thanks for sharing, just skimmed through it but it looks like they've took a really measured approach.
expired domains due to long-standing links in knowledge boxes... really nice find.
VERY nice - thank you