Athens was a direct democracy which means that all eligible citizens voted directly on bills and legislation. Citizens had input in many of the decisions that were made. On the other hand, the US is a representative democracy. This means that voters elect politicians who cast votes on the issues at hand on their behalf.
Apparently, Nerva gave the poor/general public slots of land, sums of money, and exempted people from the inheritance tax. This was to gain their favor, but his actions actually hurt the Roman Treasury.