There are lots of talk about privacy. On one hand, why do you care? You aren't doing anything illegal. On the other hand, why would you care. But in today's technology, with smart phones, watches, or even your toaster, may have information on it that you don't want everyone to know about, or you would post it on Facebook, right?
The fact is, there is no privacy, get over it! Almost everything you do is being recorded somewhere. Take a look around! In most cities, there are cameras on just about every intersection. Big brother is watching.
The FBI or local police can put up a "stingray" device, usually in an inconspicuous van, which might have a tiny antenna on it. It can tap into every cell phone call in a 1 mile area. It also can sniff your data traffic, such as emails, or even some bank transaction, but usually, these are encrypted. All they have to do is switch it on, and it instantly records all voice, text, or data calls within about a mile radius, and we are not just talking about Metadata here. Metadata is usually who called, who they called, locations, when they called, and how long, but it doesn't include the content of the conversation. These nasty little Stingrays are secret devices, used more and more by the police, FBI, DHS, and just about every other 3 letter agency, are being drooled over.
Don't even think about trying to get one. Not only are they prohibitively expensive, but they are only sold to law enforcement, military, and government organizations. Very little is known about them, because before anyone gets to use them, their potential owners must sign a secrecy agreement. It is a loophole the cops rely on, as an excuse not to talk about it. This is why they are so secret.
With my knowledge of the cell phone system, these devices usually insert themselves between you and your closest cell tower. As far as your cellphone knows, you are actually talking to your cell tower. But in fact, this "man in the middle" can not only query your cell phone, and get their locations, record the IMEI code of your phone, tap into TEXT and sniff the data from the 4G or 3G cellular data network, and triangulate your location.
The police are drooling over how nice it would be to have one at demonstrations, recording everyone's cell phone calls, in an attempt to thwart organizations, and sometimes, they just shut down the cell service completely if they (police), get pissed off enough. These things are almost impossible to be physically or electronically detected.
The true "Underground" scene, usually consisting of Preppers, or any other type, are exploring a radio mesh network, something that may not be completely "tap proof", but impossible to shut down. It requires no centralized organization consisting of cell phone towers, phone exchanges, etc. the FCC is just now starting to pay attention, but frequency scattering is now in the hands of radio enthusiasts like ham radio, or low power WIFI like devices.
So, how can I protect my privacy? The short answer, in reality, you can't, Unless..... You get off the grid completely. You either mine gold or Bitcoins, but never try to buy them these days, because the seller is obligated to take down your name.
What about communication? Forget it! Analog phone systems are being recorded, digital phone systems store your digital representative of your voice, cell phones of course, and even your local coffee shop WIFI network is being tapped.
What about encryption? It's all a matter of convenience. You have to sacrifice convenience for security. This means you have to maintain a "key ring" containing public encryption keys for everyone you communicate with. There are even "key servers" one can put their PGP public key so others can find you. Without going into a tirade explaining how all this works, Google is your friend.
What about "pre-pay" cell phones? Currently, you can get a cell phone number that is known only by the provider, and it is not tied to any specific individual, but in a few years, the USA is going to be requiring US cell phone providers to take down your name and drivers license number before activating the phone. This is already true in SE Asia, parts of the Middle East and Northern Europe and Scandinavia. The USA is last as usual, but that is a good thing in my opinion.
There is one glimmer of hope! There are apps out there for android and iPhone and iPad that provide text, voice (store and forward), and even video clips (usually very short) for communications. No record of these messages are kept anywhere, except on the recipients phone. Not only that, these messages are encrypted with mil grade encryption. I'm using wickr, because it was written by a person who has no love for the NSA. It uses perfect forward security, so even your wickr username is encrypted with a session key, Only good for a simple individual text message. The program auto-deletes your messages, and you can control how long you want the messages to persist. It's just as easy as using SMS messaging! and you only need a data plan to use it, and it's free, for both the program and to send a message, anywhere in the world. All you need is a data plan or a WIFI access.
I hope this is enlightening, and the best thing to consider, is just to assume they are watching you, but just don't get overly paranoid about it. There is always safety in numbers, at least Darwyn thinks so.