Basically is a running oriented option game out of the spread. BIB did a good job explaining it but very effective and with the addition of some RPO out of it REALLY hard to stop.
Only thing that can really stop it is SPEED. In the 70's & 80's the classic I and wishbone option teams were power oriented and Miami, FSU, etc attacked it with SPEED and killed it. Hence the rise of those two programs - take OLB make them DE, take SS and make them OLB, etc and have big nasty DT's. That way you stop the inside run and have the speed to cover the option.
The spread passing game was introduced and changed the game 15 years ago and now some innovative coaches figured out that combining the spread and option oriented running games is a nightmare for Defense. Auburn is another great exmaple of this.
A few key things -
1) the spread aspect causes the D to spread out allowing for the dives to be very successful
2) once the dives are successful the D sucks back in the middle the outside run stats clicking
3) Once the D sells out to stop the option the RPO opens up
Damn nightmare to stop and requires POSITION AND ASSIGNMENT defense which isn't as easy to do as it sounds.
Its basically a option heavy version of the Veer & Shoot