They say you should only believe half of what you see, and none of what you hear. You probably shouldn't believe much of what you read on the internet, either.

The web's immediacy and lack of institutional fact-checkers makes it a perfect platform for rumormongers and pranksters to swindle people into believing the unbelievable. It's why Justin Bieber, despite being very much alive, has died many, many deaths in the Twitterverse.

Of course, it's not just the internet's fault. People have been pulling hoaxes for millennia, probably dating back to the Stone Age when one caveman convinced a bunch of other cavemen that woolly mammoths were friendly (they weren't).

But this year in particular has been a banner year for hoaxes, so much so that I suspect we may find out that 2013 itself was one big lie.

Here are the most memorable:

Google's fictional class warfare
In December, protesters blocked a Google bus — yes, the company has private bus lines — as it made its way through the streets of San Francisco. That's when a supposed Google employee hopped down and unleashed a tirade dripping with preposterous elitism: "Why don't you go to a city that can afford it?" he shouted at the protesters. "This is a city for the right people who can afford it. You can't afford it? You can leave. I'm sorry, get a better job."

The man was like a feverish Occupy Wall Street caricature of a businessman. And it turns out that's precisely what he was. He was actually a labor organizer and Occupy protester himself, and the whole confrontation was part of the protest.

Maybe reporters covering the "story" could have, I don't know, Googled the guy's name before splashing him all over the internet?

The lying waitress
In November, Dayna Morales, a New Jersey waitress, alleged that a family dined at her restaurant and then stiffed her on the tip because she's gay.

"I'm sorry but I cannot tip because I do not agree with your lifestyle & the way you live your life," read a handwritten note on a receipt Morales submitted to the organization Have a Gay Day. The story soon went viral, and people donated more than $3,000 to Morales, money which she said she would pass along to the Wounded Warrior Project.

Two weeks later, the supposedly cruel family came forward with their own copy of the receipt, sans hateful message and showing a tip, too. Furthermore, it turned out Morales never forwarded the thousands of dollars in donations. Once reporters dug deeper, they discovered that Morales had a long history of lying: She had previously claimed that she had brain cancer, that her home had been damaged by Hurricane Sandy, and that she had served in Afghanistan.

Morales has since refunded at least some of the donations. She was also fired.

The ugly baby
As hoaxes go, this one had a long shelf life.

Last year, a story out of China claimed a man had sued his wife for birthing an ugly baby. The story (which, full disclosure, we covered, too) went like this: The woman had undergone plastic surgery years earlier unbeknownst to her husband, so the baby came out looking like her old ugly self. The man, feeling he'd been duped into having a less-than-beautiful child, sued, alleging false pretenses.

The story popped back up this year with a supposedly new picture of the couple, and that's when people finally started asking questions. As it turned out, a version of the story had been kicking around for a decade. The newfound picture was actually, as the Huffington Post pointed out, taken from a weird ad for plastic surgery.

So while the story did tangentially involve plastic surgery and ugly babies, it did not involve a litigious husband. And even those parts of the story that were real were technically, at first, fiction.

Amazon letters to Santa
As a kid, you may have written letters to Santa describing what you wanted for Christmas. And if you were a particularly precocious child in the digital age, you may have even tapped out a letter to Santa Claus on your iPad delineating your Christmas wish list.

But even if you were a tech-savvy toddler, you probably never would have written out a wish list, in crayon, as one enormous hyperlink, as one child supposedly did this year. Still, the list fooled many on the web. Reddit sleuths even deduced the hyperlink pointed to a remote controlled car.

Nevertheless, the letter, like Santa, was a fake. It was a two-year-old piece of satire from the blog The Inclusive. "If people are enjoying it more thinking a kid wrote it, I guess that's fine," the writer, grown man Zack Poitras, told Mashable. "I ultimately made it to make people laugh, not to prank anyone."

Andy Kaufman's last act
Conspiracy theorists have long posited that legendary comedian Andy Kaufman, who died in 1984 of cancer, faked his own death. That would sort of fit in with Kaufman's odd persona, which is why many were willing to believe a 24-year-old woman who, at the annual Andy Kaufman Awards in November, claimed she was Kaufman's secret daughter, and that her father faked his own death to raise her in secret.

Adding credence to the claim, Andy's brother, Michael, also said at the event he'd received a letter from Andy 15 years after the comedian's supposed death. And he said Kaufman had written when alive about maybe wanting to fake his own death.

Days later, Michael claimed he'd been duped. "Now that it's Thursday, not Monday anymore, I believe I am part of a hoax," he told CNN. The woman claiming to be Kaufman's daughter turned out to be a young New York actress, Alexandra Tatarsky.

As Kaufman's former manager, George Shapiro, put it to CNN: "Andy's very much alive in our hearts, but I don't think his body is around."

The fake twerk fail
"Twerk" may have been robbed of "Word of the Year" honors, but it was nonetheless a strangely important part of the cultural lexicon in 2013. And in the non-Miley Cyrus division, no twerk stood out more than the one that supposedly went wrong and resulted in some serious burns.

In September, millions of people watched a home video of a woman twerking her way into a fiery crash with some lit candles and a glass table.

But after the video received air time on the major networks, blogs, and cable news, comedian Jimmy Kimmel revealed on his late night show that he'd staged the whole thing as a little experiment in the power of web hoaxes.

"Thank you for helping us deceive the world and hopefully put an end to twerking forever," he told the actress who played the fake twerker.

Sadly, Kimmel was wrong, and twerking has persisted to this day.

The NASA letter too good to be true
Many kids grow up wanting to be astronauts. Others grow up and decide they'd rather mess with astronauts.

Such was the case with Janie Jones, a British man who claimed to have received a hilarious letter from NASA in response to a ludicrous letter of his own.

Unfortunately, NASA denied writing the letter, which they totally would. Given that the agency is hiding the existence of extraterrestrials, why wouldn't they lie about a little snarky bit of snail mail?

Well, because Jones is a noted fibber who's made the same joke in the past with different subjects. Kudos to NASA for at least having a sense of humor about it.

Diane in 7A
Over the long Thanksgiving weekend, a too-good-to-believe story played out on Twitter: An obnoxious airline passenger named Diane just wouldn't shut up, and a heroic man chronicled his epic, escalating note-passing feud with her, complete with pictures.

The feud "won Thanksgiving," according to BuzzFeed, except it turned out that the whole thing was a lie. The first clue it was staged: The Twitter user who concocted it, Elan Gale, is a producer on a TV show, The Bachelor.

Pro tip: Don't assume someone whose day job involves marketing fiction as reality is telling you the truth — especially on Twitter.

Manti T'eo's non-existent girlfriend
Manti T'eo was a standout football player at Norte Dame with a tear-jerking story. A Heisman finalist, he led the Fighting Irish to a national title game mere months after the deaths of his grandmother and girlfriend.

The part about his grandmother was true. However, in a bizarre twist that caught even T'eo by surprise, his girlfriend didn't die. That's because she couldn't: She didn't exist.

T'eo was actually the victim of a long, weird catfishing scheme perpetrated by an acquaintance, Ronaiah Tuiasosopo. He'd apparently been led to believe, via long-distance phone calls, that he was in a committed relationship with a fictional woman, Lennay Kekua. Tuiasosopo ultimately admitted to the hoax, saying he'd fallen in love with T'eo and used Kekua's fake story as an "escape."