Cheap, self-replicating, wireless nanobots (nanoscale-robots), or 'motes' (short for remote robots), used as sensors by the nanorati ('nanotechnology lierati', or elite scientists)... that can communicate, moniter and send data or accomplish nano-scale tasks.
-micro machines/ microbots.
-nanoassemblers (or 'assmeblers' for short).
-MEMS: microelectronic mechanical systems.
-software TinyOS: Weenix (LinuxOS-using nanobots)/ Weendows (Windows).
-photovores (nanobots that feed on sun-light, also known as 'heliovores'.
-gastrobots: feed on organic sugar.
A wild and really off-the-wall theory had recently emerged when one scientist predicted that 'smart dust' (these tiny, little nanostructured machines that can collect 'atoms' from the air!) will in a couple of decades lead to what he called the 'global ecophagy' theory : these nanobots come eqiupped with small nanoscal-blades and thus capable of eating away at the whole Earth, leaving in their trail what became known as 'grey goo'! Some other, even madder scientists have also predicted that there would be other 'police' nanobots that will control the others' action and named these 'blue goo'!
Any way, seriously there is today quiet a concern for what is called 'nanotoxicolgy', or nanopollution: the prediction of the harmful effects nanos can make on the 'nanosphere' and the impact of using AMOs (atomically-modified organisms), that are basically GMOs on atom-scale manipulation.
Finally, there's a new role that nanotechnology is playing right now in bringing together different sciences and pitting them together to create a stranger-than-fiction new one: NBIC (nanotechnology, biotechnology, information and cognitive science) that long-awaited science that can make the TransHuman dream a reality!