Contrary to what some brands may think, generating viral content requires, above all, figuring out what makes users feel compelled to share rather than just click. If you think about some of the content that struck fire on social media in 2014, that fact becomes crystal-clear.

There was “Gangnam Style,” which ended up surpassing 2 billion views and breaking YouTube’s views counter, and then there was WREN’s fascinating “First Kiss” video that graced our Facebook feeds. Perhaps most memorable was the awe-inspiring and inescapable Ice Bucket Challenge, which generated $113.3 million as of September 2014, for the disease amyotrophic lateral sclerosis (ALS)—an accomplishment due in large part to its number of social shares.

Turns out, these campaigns have a lot in common. And dissecting just what makes something go viral can help brands figure out how to make their content earn similar fame.

Here are six takeaways from viral content last year, based on the content that fueled them:

1. Stay positive

“Virality is partially driven by physiological arousal,” write the authors of a University of Pennsylvania study that suggested users were more compelled to share happy than sad content. Their findings aren’t surprising—after all, who likes a Negative Nancy? Scientists at China’s Beihang University studied emoticons on a microblogging platform and similarly found content that made users happy outpaced the sharing of other content that made users feel sad or disgusted.

The aforementioned “First Kiss” video, which has racked up 94 million YouTube views and counting, is an example of how generating positive feelings can compel users to share.

Humor is also important: Research by Canadian e-business development company Computan found that among the four primary types of viral content—funny, emotional, polarizing or promotional—that of the humorous variety is the most likely to be engaged with. “Gangnam Style” or even Geico’s famous “Hump Day” commercial that flooded the Internet last year—are instances of how humor can strike a nerve with readers.

2. Know your audience

Figuring out which emotion to play to is based strongly on the demographic and gender at hand, as science shows different age groups react differently when it comes to sharing.

“Positive feelings alone do not an image make,” argued digital marketing agency Fractl, which studied how 800 people reacted to 23 different online images.

Fractl determined content that elicits a mixture of emotion, including positive and negative feelings, was more likely to be shared than content that was only positive. That rule holds especially true for millennials, who are the most digitally connected generation today. This group showed the least response to content that was just positive or held an element of surprise, which suggests that these people prefer content that has an element of novelty or intrigue.

As far as gender differences go, when seeing images, men in the Fractl study reported feeling more joy toward images but had a smaller range of emotions compared to women. Women, on the other hand, exhibited more trust emotions and a greater emotional complexity toward images. That suggests women may be more likely to share images compared to men because they are more receptive to a larger range of emotions—and, namely, trust.

3. Go big or go home

Based on Web viewers’ short attention spans, it may seem counterintuitive to think that longer content is more shareable—but that’s actually true, at least according to one report.

Content discovery and Web research tool BuzzSumo tracked the sharing of 100 million pieces of content and found that bigger is better when it comes to content length. Based on its analysis, the company found that content with at least 2,000 words in length garnered the most shares.

That truth seems to be lost on many brands today: In BuzzSumo’s report, there was up to 16 times more content with less than 1,000 words than there was content with 2,000+ words.

4. ‘Social good’ sells

The Ice Bucket Challenge is a prime example of how having a cause can generate shares: The ALS Association raised just $50,000 in 2013, but thanks to its social media campaign earned $113.3 million in total, the Wall Street Journal reported in September.

"It just became craziness. Good craziness, but craziness," Barbara Newhouse, president and chief executive of the ALS Association told the Wall Street Journal.

According to a New York Times analysis, the videos—where participants dumped a bucket of ice over their heads and made a donation before nominating friends to participate as well—encouraged some 26,000 people to donate for the first time.

Knowing your brand’s cause and adding a philanthropic element can translate to shares, and the Ice Bucket Challenge illustrates just that.

5. Video is powerful

Have you heard about the new crop of online tween vloggers who earn millions by playing up their personal brands on YouTube? Apparently, these vloggers—bloggers who deal primarily in video—have gained fame not only because they are entertaining. Their viewers also appear to trust them more than traditional celebrities.

The five celebrities that teens ranked highest in a survey published by Variety were all YouTube personalities. The results essentially indicated that the teenagers polled associated these stars with more authenticity and were less subject to PR sway, so they trust their opinions more than celebrities not using the medium.

Communicating your brand’s message via YouTube is one way to level with your audience and inspire a similar relationship.

6. Choose your words carefully

Based on a marketing study of 2.6 billion shares, released in summer 2014 by Fractl and BuzzSumo, there’s no perfect formula for a shareable post when it comes to language. Each brand has its own code for virality that it must develop for each social site—be it Twitter, Facebook or LinkedIn.

Three golden rules for writing a shareable piece of content did hold true regardless of the social site at hand: positive adjectives, knowledge-based verbs and the promise of photos.