Below is a link to an analysis by one of the staff writers at The Key Play. It's a good read for those who've heard a lot about it, and why VT ran it better than anyone else who played it against OSU.
http://www.thekeyplay.com/virginia-tech-football/2015/09/10081/depth-analysis-hokies-bear-defense
For those who want the TL;DR version: VT's defensive front is faster than anyone else who played the bear against OSU, and it's not a drastic departure from the way we generally play. The VT front 7 generally plays "gap fit," which is a departure from most D-1 schools traditional base defense.
Game week is finally here, and I'm pumped!