I believe reddit has historically done something similar. Rather than having a given article's ranking decay over time, they simply hand out better ranks to ne

I believe reddit has historically done something similar. Rather than having a given article's ranking decay over time, they simply hand out better ranks to newer articles, leading to continual inflation. A naive example of this sort of ranking would be (timestamp in hours + upvotes - downvotes). This would make your (excellent) idea easy to implement, because you could just use an autoincrement key as the timestamp, ignoring any sort of decay calculations.