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Anyone who can watch you will watch you.

In technology, that is one of the big lessons of 2013. The National Security Agency and who knows who else have been tracking this or hacking that. China has been breaking into our computers. Google has been sifting through our home networks. Facebook has been tinkering with its privacy settings.

No wonder outfits like Snapchat have exploded onto the scene. They seem to go against the grain, holding out the promise that all those selfies, texts and emails will simply vanish.

Whisper, an “it” app for teens, supposedly lets people share secrets anonymously via smartphone. Telegram is being pitched as the adult version of Snapchat.

But the fact is, many services that claim to offer that rarest of digital commodities — privacy — don’t really deliver. Read the fine print.

“Just because information is unavailable to you and you don’t see it doesn’t mean that it is not being captured, stored, or even seen by someone else in transit,” said Edward W. Felten, a professor of computer science and public affairs at Princeton.

Snapchat’s privacy page explains that private images are stored on someone’s phone — and on its own servers. “Forensically, even after they are deleted,” Snapchat says, those images can be retrieved. Whisper’s privacy page says the company owns the intellectual property, both images and text, that people post; Whisper reserves the right to sell that stuff to third parties. And Telegram, while seemingly less innocuous with its claims, nonetheless leaves out something you might want to know: someone can just take a screenshot or picture of that “private” conversation.

“Even if there are all sorts of technical barriers that the disappearing messaging services put up there, someone can just take a picture of the phone,” said Kurt Opsahl, a lawyer with the Electronic Frontier Foundation, a civil liberties organization. “If they can see it with their eyes, they can see it with a camera.”

In most instances, your Internet service provider or cellphone carrier gets to watch over your shoulder with every click.

Even when these messaging apps aren’t tracking your chats, the N.S.A. and other government agencies are. They’re everywhere. Even people who play fantasy video games like World of Warcraft are being watched, according to documents leaked by Edward J. Snowden.

Worse, the snooping doesn’t just happen on our desktops and laptops. In our mobile-centric world, it happens everywhere. Through our mobile phone, our locations are being corralled and calculated. The N.S.A. can even figure out who we are with by triangulating phones’ previous locations.

Don’t have a smartphone yet? They still know where you are and where you’ve been. The American Civil Liberties Union released a report this year that found that technologies that let governments scan license plates are being used to build databases of vehicle locations across the United States.

The N.S.A. didn’t respond to a request for comment, but the argument by some companies and government groups is that if you’re not doing anything wrong and have nothing to hide, then you have nothing to worry about.

Privacy experts strongly disagree. A new book by Harvey Silverglate, a lawyer in Massachusetts, titled “Three Felonies a Day,” claims the average professional in the United States commits at least three crimes every day. How? While academics, lawyers and even government officials don’t actually know how many laws exist in today’s judicial system, it’s estimated that there are from 10,000 to 300,000 federal regulations that could be enforced criminally.

Mr. Opsahl said we all probably break some of those laws online every day, too. “There is a tremendous amount of information that is available about every person online, and the practical ability for government and private surveillance has never been greater,” he said.

So if you can’t find privacy in a game with trolls and goblins, on a Sunday drive with your family or inside a messaging app with disappearing chats, what can you do?

“What’s clear is that tracking technologies have outpaced democratic controls,” said Ben Wizner , the director of the Speech, Privacy and Technology Project at the A.C.L.U. “What we’ve learned this year is that agencies are determined to conduct surveillance on us, and there’s not a whole lot we can do about it.”

But there is one thing that Mr. Wizner said can and should happen. Technologists are capable of building tools that can prevent such snooping — things that go beyond disappearing messaging apps and that could protect everyone’s privacy.

“This may be one of those once-in-a-generation moments when we recalibrate the powers of the citizens and the state,” Mr. Wizner said. “And that change can happen on the technological side, where the technologists that are disillusioned by the incessant tracking will use their skills to make surveillance more costly.”