The first time it was "abandoned" was IMO just due to lack of community interest. PND was originally launched as an "anti-Wolong" coin. When it succeeded in that mission the community pretty much dumped it. However a short time later it saw a revival with what seemed to be a very adept development team and it rose from the ashes. To the best of my knowledge there was some shenanigans behind the scenes from one of the devs, and when he left it had a sort of domino effect on the rest. We never really got a clear explanation as to why. This time, however, the community hasn't given up on the coin and has stepped up to the plate to restore it to it's former glory.