Smart Meters can read your thoughts and send them to Obama.
You are joking, I know, but I have read comments online of people thinking serious thoughts along those lines.
As a DESIGNER of these things, I know: the poor little things barely have the processing and communication capability to get done their primary mission, which is reporting consumption so the utility can plan for surges, and can do billing.
There ain't no bytes, cycles, or transmissions left to spy on you!