The short answer is YES it can – provided the data recording is sufficiently granular.
Anything you watch on TV is going to have a pattern of light and dark screens. Your TV set will draw more current when displaying a brightly lit scene than a dark scene. The result is that each TV movie or other TV program you watch will generate a kind of “signature” of variable electric current through the meter.
Now if the meter records data in very fine intervals, this signature will become visible in the data and can be matched against the signatures of all programs known to be broadcast during that time period. This process has only to do with how short the recording intervals are, and nothing at all to do with how often data is uploaded to the utility by radio or other means.
In any system with very short recording intervals, someone is likely to develop an application that will mine the stored meter data and automatically generate a profile of all content watched for each household. Advertisers would be interested in receiving reports generated by such an application.
Two hackers proved all this feasible when they hacked into a system developed by a German manufacturer that was recording data in two second intervals. Click here for the full story as reported on msnbc.