Research published in a recent edition of Science suggests that analyzing patterns of cellphone use which includes locational data could be upwards of 93% successful in predicting the behavior patterns of users.
Combining this with sorely lacking privacy features that most social network users fail to toggle "on" in their account settings which allow datamining services like RapLeaf to compile, the ease of IP Address identification and new techniques for tracking people's locations based upon email trace routes being developed by Google, I am sure that astute weilders of information tools could get this certainty up by a few more percentage points.
Heck, enable your pda, notebook, tablet computer or cellphone with GPS and I can locate you 100% of the time, minus when you forget the phone in a bathroom or leave it at work.
In one American school district, a high school principal is defending the use of webcams to record student activities at home (after school hours and off school grounds). The laptops issued by the public school to the students would turn on randomly at all hours of day and night, as the school administrators spied on students remotely through the webcamera built into the laptops. One student was suspended for popping "pills" which turned out to be candy treats.
In the UK, the situation is just as dire. People under house arrest, probation or parole are monitored in their homes by closed circuit television cameras. One family was placed under criminal investigation by child protective services, because they were seen to allow their child to stay up and watch television past a reasonable hour, hence endangering the child's welfare. Can we now safely cry out "nany state", anyone, or is this just a paranoid rant?
Lets flip back to America for a moment and discuss how your television watches you. A dear and recently departed friend told me that my television might be surveilling my activities. I dismissed Wilbur's rantings from the Patriot / Common Law / Militia community as a paranoid delusion. Within months, however, a new generation of big screen televisions were on the market bearing cameras with facial recognition technology built into them. This allows the tv to recognize the viewer, turn on, and surf directly to their favorite channel much like Dell laptops running Win7 do now (run by BestBuy online if you don't believe me). Within weeks, a hacker had cracked the television and demonstrated how to remotely access the camera through the internet. Your cable television feed can be a window for others to watch you eat Cheetos on the couch in your underwear, so beware!
Citibank terminated a bloggers bank account for posting anti-banking opinions online. Whether corporate surveillance of people or government intrusion on the privacy of rights of citizens, these trends are part of a dance wherein the individual must take responsibility for his role in securing his information, while the outside world must bear consequences for transgressing reasonable boundaries of good citizenship and polite social demeanor.
Technology like this falls easily to more ancient tech. The powerful and arcane science of electricians tape has magically managed to disable many of these mighty and mysterious tools. The use of device options to "turn off" the public features and "turn on" the privacy options can also derail the best efforts of people to locate you... that is, IF and only IF, you have not already put all of this data on the internet for years or decades (remember, what's already out there is on the net forever).