Most companies are ill equipped for a social media crisis, according to a study from this year. That’s bad news for brands, given not only the prevalence of social media but also because roughly half of this year’s biggest PR blunders were committed on Twitter.

To determine these public relations gaffes, PR Daily turned to its readers, asking them on several platforms—most prominently our Google+ page—to name the year’s biggest screw-ups.

Upon receiving the answers, PR Daily editors locked themselves in a windowless room for days—consuming nothing but tepid coffee and random leftovers from the company fridge—to compile the final rankings.

And here they are, the top PR blunders of 2011, according to PR Daily readers.

10. Charlie Sheen’s meltdown

Given all the big stories of 2011—uprisings, natural disasters, brinksmanship in Washington—it’s easy to forget Sheen, whose very public meltdown and personal mantra #winning became a popular topic of discussion last spring.

The whole mess started with a radio interview, in which Sheen waxed nonsensical about a range of topics and spewed venomous comments about Jews. As a result, Sheen’s publicist quit and CBS fired him from “Two and a Half Men.” That didn’t stop Sheen from taking to Twitter, where he set a Guinness record for the Twitter account that reached 1 million followers fastest.

Just when it seemed Sheen had pulled some kind of social media coup on the Hollywood establishment, he embarked on a highly anticipated speaking tour. Ticket buyers walked out and demanded refunds, and the Sheen train—already derailed—ground to a halt.

Despite his erratic behavior and history of female abuse, we will always love his role in “Ferris Bueller’s Day Off.”

9. House Republicans and the middle-class tax cut

This is the PR Daily staff’s lone entry in the top 10 list, having not received a vote from readers (perhaps because it hadn’t yet happened when they were asked to cast their ballots).

Republicans in the House of Representative this week rejected a bipartisan proposal from the Senate to extend middle-class tax cuts and unemployment benefits for two months, during which time Congress would attempt to draft a long-term proposal.

The move has left media pundits on both sides of the aisle in a state of bewilderment—how could the party of no taxes be OK with a tax increase on the widest swath of Americans?—prompting even the conservative Wall Street Journal editorial board to call it a fiasco.

“GOP Senate leader Mitch McConnell famously said a year ago that his main task in the 112th Congress was to make sure that President Obama would not be re-elected. Given how he and House Speaker John Boehner have handled the payroll tax debate, we wonder if they might end up re-electing the President before the 2012 campaign even begins in earnest.

“The GOP leaders have somehow managed the remarkable feat of being blamed for opposing a one-year extension of a tax holiday that they are surely going to pass. This is no easy double play.

“Republicans have also achieved the small miracle of letting Mr. Obama position himself as an election-year tax cutter, although he's spent most of his Presidency promoting tax increases and he would hit the economy with one of the largest tax increases ever in 2013. This should be impossible.”

If the House GOP’s move in the latter part of 2011 helps drive Obama’s approval rating north, furthering his chances for reelection in 2012, this may go down as the biggest PR blunder of 2011—for Republicans, at least.

8. Knocking Detroit drivers when Chrysler is your client

Another social media miscue: A New Media Strategies employee, who was working on the firm’s Chrysler account, thought he sent this tweet from his personal account:

“I find it ironic that Detroit is known as the #motorcity and yet no one here knows how to f**king drive.”

Except he didn’t send it from his personal account; the tweet came from one of Chrysler’s official feeds. As a result of the mistake, New Media Strategies fired the employee, and Chrysler dropped New Media Strategies.

Meanwhile, everyone else who works in social media prayed to the Twitter gods that they would never make a similar mistake.

7. The Rupert Murdoch phone-tapping scandal

The phone-tapping scandal, in which employees of News Corp.’s London tabloid News of the World listened in on voicemail messages, isn’t the PR scandal. That’s a terrible (and illegal) ethics breach by a media outlet. Instead, it’s how the Murdoch-owned company handled the scandal—it shuttered the entire newspaper—and that several PR professionals were involved in the mess.

Andy Coulson, the top press aide for British Prime Minister David Cameron, resigned amid scrutiny that as editor of News of the World he played a part in the scandal, while at least 10 press officers at Scotland Yard were suspected of being in cahoots with News Corp.

6. Kenneth Cole’s tasteless Cairo tweet

Can’t blame this social media gaffe on a lowly intern, because the offending tweet came straight from the top. As protesters poured into the streets of Cairo in early February—flooding Twitter with updates about the emerging revolution—fashion mogul Kenneth Cole jumped into the online fray with a promotion for his spring line:

“Millions are in uproar in #Cairo. Rumor is they heard our new spring collection is now available online.”

Cole took a beating for that one, prompting him to quickly apologize for the offending tweet, which the company also deleted.

The move was so senseless that some even wondered whether Cole had sent the tweet knowing it would cause an uproar and draw more attention to his brand—a sort of, “I don’t care what you say about me as long as you spell my name right” approach.

Perhaps most notable about the Cole gaffe is that it was the first of many social media mistakes to come in 2011. In that sense, Cole is a pioneer.

5. Lowe’s angers Muslim-Americans

With the exception of the payroll tax cuts, the Lowe’s debacle is the most recent gaffe on this list, starting in early December when the hardware chain pulled its ads from a TLC show “All-American Muslim” after a conservative group expressed concern.

Clearly, no one from Lowe’s watched the show—nor checked out the absurdity of the group making the claims—before it made such a drastic move.

The backlash online was swift and furious. People crowded onto the Lowe’s Facebook page, unleashing vitriolic comments about the brand. Ultimately, Lowe’s apologized and explained its actions, but it wasn’t enough to stem the tide of negative sentiment. Tempers are still simmering over the company’s decision.

4. The Anthony Weiner debacle

It will forever be known as pulling a Weiner: tweeting something publicly that was meant to be private. In former Rep. Anthony Weiner’s case it was a picture of his penis, sent to a young woman who wasn’t his wife. The picture, which was just of the politician’s underwear-covered groin, briefly appeared on his Twitter feed before it was deleted.

That was a disgusting and embarrassing mistake. Even more awkward, however, was his handling of the incident.

Instead of owning up to the mistake, he lied to the public and press, claiming someone had hijacked his account. It’s difficult to say whether Weiner would still have his congressional seat had he come clean right away, but his deceit ensured his political demise.

3. Bank of America’s surcharge

Banks are suffering a personality crisis. They went from villains of the corporate world because of the economic meltdown of 2008 and subsequent recession to a higher profile as the archvillains of 2011, thanks to the Occupy Wall Street movement.

With such simmering resentment toward the banks, any move perceived as anti-consumer would be viewed poorly in the public eye. Despite this obvious notion, Bank of America issued a $5 monthly surcharge on customers who use their debit cards.

Customers expressed outrage; many took their business elsewhere, and, ultimately, the bank reversed its decision. The PR debacle, along with the lingering effects of the recession and fears overs Europe’s debt crisis, has helped weaken the company’s share value. This week, Bank of America’s stock price fell below $5 a share.

2. Penn State’s handling of the Sandusky scandal

It’s tough to call this one a public relations gaffe, because it is a human tragedy of sickening proportions.

Jerry Sandusky, the longtime defensive coordinator at Penn State University, allegedly sexually abused young boys. Top university officials, including head football coach Joe Paterno, allegedly knew about at least one of the incidents and failed to alert police.

The PR aspect enters when it comes to the university’s crisis communications.

Penn State’s initial statement from President Graham Spanier about the matter threw the university’s support behind the officials who allegedly covered up Sandusky’s behavior, while ignoring the victims of the tragedy.

University trustees followed up with more-appropriate remarks, but it wasn’t enough to undo the damage caused by the school’s tin ear.

What could have been a horrible incident—involving a few, albeit key, members of the organization who were identified and dealt with—became an institutional scandal, calling into question the very mission of the school.

Making matters worse (from a PR standpoint) is that the university knew for months about the grand jury investigation that led to the charges against Sandusky, yet it was ill-prepared when the news went public.

1. Netflix

Can bad PR relations sink a company that has revenue approaching $1 billion? Hard to say, although Netflix seems to be the canary in the mine.

The movie-rental service expects its first year in the red, owing to a mind-boggling rebranding effort, which started with a poorly written and ill-timed announcement that it would raise its prices.

To grasp the foolishness of Netflix’s actions, let’s start with the price hike in July.

In a slapdash blog post, the company unveiled a price hike, which it framed as savings for its customers. Basically, it was unbundling its DVD-by-mail service and its video-streaming business. All told, the price hike amounted to a couple of dollars a month; it seemed to be Netflix’s tone-deaf announcement that sparked such anger.

And, oh boy, was there anger. Who knew people could get so mad over movie rentals? Social media users dumped negative comments on the Netflix blog, Facebook page, and through Twitter. The company stayed mum.

Although Netflix was losing a yet-unknown number of subscribers over the hike, cooler heads started to prevail until CEO Reed Hastings decided to chime in.

In a September blog post, Hasting blamed the lousy reception of the price hike on the company’s poor communication. “When Netflix is evolving rapidly, however, I need to be extra-communicative,” he said. “This is the key thing I got wrong.”

Then, Hastings and friends committed another blunder—by announcing the rebranding of the company. The DVD-by-mail group would spin off into a separate company called Qwikster, while the video-streaming unit would operate under Netflix.

This move brought a host of problems, among them that the websites for Qwikster and Netflix didn’t communicate and that the company apparently failed to check whether the Qwikster Twitter account was available.

It wasn’t. The account was manned by a teenager with a penchant for foul language and references to drug use. Oops.

Backlash over the move was so severe that Netflix ultimately abandoned the plan. In an interview with The New York Times Magazine, Hastings blamed all the screw-ups on the company’s moving too fast.

In its third-quarter earnings report, Netflix said it had lost 800,000 subscribers, causing its stock price to plunge.

It’s been quite a year; we can hardly wait for 2012.