According to Mihail Roco, from the US National Nanotechnology Initiative, there are four different generations of nanotechnology.
First, between 2000 and 2005, there were the passive nanostructures. This was followed by the active nanostructures between 2005 and 2010.
From 2010 and 2015, the third generation appear, and Roco called it systems of nanosystems.
Since 2015, we are currently in the molecular nanosystems generation. This is meant to last until 2020, when another generation will also commence. However, Roco has not made any predictions in that sense.