What limits should be applied to mind reading technology?

“By scanning blogs of brain activity, scientists may be able to decode people’s thoughts, dreams and intentions,” writes Kerri Smith in Nature Magazine.

Image via Nature

Although companies are starting to pursue brain decoding for a few applications, such as market research and lie detection, scientists are far more interested in using this process to learn about the brain itself. (Scientific American)

Today’s Question: What limits should be applied to mind reading technology?