There are increasing numbers of new devices that can collect telltales about your mental state. George Orwell's 1984 may have been an underestimate of the amount of state control of people that may soon be possible.
Your television could soon be watching and listening to you in order to deliver a more personalized experience, and of course a more personalized series of advertisements.
New DVR will use camera and microphone to target advertisements based on recordings of users
http://news.yahoo.com/blogs/sideshow/dvr-camera-microphone-target-advertisements-based-recordings-users-014434311.html
This isn't news, as Google filed its patent back in 2007.
Google TV Might Watch You, According to Patent
http://gizmodo.com/277162/google-tv-might-watch-you-according-to-patent
But companies and governments will be able to go further than just watching and listening to you. Through implantable devices, they will record heart rate, blood pressure, and other chemical signals inside your body. Already Medtronic refuses to share this data with the people who have the devices implanted within them, even though it is their bodies that are the authors of the information stream being collected by the Medtronic device.
Who Owns Your Health Data?
http://science.slashdot.org/story/12/12/03/144245/who-owns-your-health-data
Heart Gadgets Test Privacy-Law Limits
http://online.wsj.com/article_email/SB10001424052970203937004578078820874744076-lMyQjAxMTAyMDMwMDEzNDAyWj.html?mod=wsj_valettop_email#project%3DHEARTDATA%26articleTabs%3Darticle
Wearable devices about the size of a standard company ID badge have already been created, tested, and verified in operation. Although the headline purpose is increasing the happiness of employees, you can imagine where else the technology might go.
Can happiness in the enterprise be engineered?
http://www.smartplanet.com/blog/bulletin/can-happiness-in-the-enterprise-be-engineered/7163?tag=nl.e660&s_cid=e660&goback=.gde_138801_member_192315721
The deeper and more technical article on wearable "happiness measurement" badges is at the IEEE site:
Can Technology Make You Happy?
http://spectrum.ieee.org/at-work/innovation/can-technology-make-you-happy
But even if you aren't implanted or badged, there are ways to pick up cues about your mental state. Facebook has dedicated itself to "trying to help users map out all the things they care about and all the things they’re connected to, and to help people discover things through the lens of their friends":
How Facebook’s Top Engineer Is Trying to Read Your Mind
http://www.wired.com/business/2012/11/mike-vernal-facebook/
