This is just reviewing what is currently available for mundane spying. The point is that nanotechnology is not needed for perfectly adequate spying on the average person.
More useful surveillance information can come from:
your phone records, online activity, credit cards and financial info. All of which can be easily tracked. Plus there are a billion camera phones and digital cameras already.
Below are some sites for commercially available spy gear.
These are covert listening devices or detection devices. Professional grade gear can cost $10,000. More expensive gear has higher quality microphones, more channels for recording, a writable optical drive for the recordings etc…
Spy detection spy nyc