Back in early 2014, the consensus mechanism that eventually became DPoS was actually the first blockchain design problem I ever attempted. At the time I was just a community member flaming the forums with my opinions on how BitShares should be built. (I'd mined a meager handful of PTS, and wanted to do what I could to help the yet-to-be-built BitShares succeed.) I just wrote a post about the early history of DPoS with my own perspective and memory of details from those days.