Reddit users tend to look for funny stuff around lunchtime, a new analysis suggests. Reddit screenshot

To increase your spiritual karma, you will probably want to go out and do some good deeds. To increase your Reddit karma, you may want to spend your lunch break reposting a funny picture of a top hat-wearing bear riding piggy-back on Abraham Lincoln.

Marketers, editors, artists and writers alike may salivate at the thought of discovering the secret to what makes something go “viral.” Now, a group of Stanford University computer scientists thinks they’ve cracked some of the secrets to popularity on Reddit.

“There's a very high chance that your content will get missed out on Reddit," Stanford scientist Himabindu Lakkaraju told New Scientist on Monday. "We basically asked whether branding is important on Reddit, and it turns out it is."

To understand what factors play into online popularity, Lakkaraju and her colleagues traced the path of a single image: the afore-mentioned bear and Abraham Lincoln digital painting by artist Matthew McKeown. When first posted in Reddit’s “pics” subforum, the piece did decently, garnering 62 points of karma. But when reposted a year later in the “funny” subreddit (under the title “MURICA”), the painting received more than 600 karma points.

When the researchers did a wider analysis of more than 132,000 submissions, they saw that Reddit tends to repeat itself – images within the dataset were reposted about seven times, on average. While Reddit users typically have a negative reaction to reposts, the collective memory isn’t all that long – just about 45 days is enough for a repost to not draw scornful comments. Midday is the best time for posts on big subreddits like "atheism," "gaming" and "pics" to go viral.

The scientists fed what they learned from their analysis of the most popular posts in the data set into an algorithm, to see if a machine could predict a post’s success based on word combinations. The algorithm performed admirably, but sometimes missed a few of the biggest and most popular posts. Popularity, it seems, requires a certain je ne sais quoi that can’t quite be untangled by an equation or a marketing analysis.

Lakkaraju and her team will be presenting their work later this week at the International AAAI Conference on Weblogs and Social Media in Cambridge, Mass.

In a similar vein of research, a trio of Facebook employees recently examined what happens when photos on Facebook go viral. In their paper – also slated for presentation at the AAAI conference in Cambridge this week -- they studied two particular cases where photos were reshared many times. The first is a photo of President Barack Obama and his wife Michelle, posted shortly after Obama won reelection. The second is a photo of a Norwegian man Petter Kverneng and his female friend, with the man holding up a sign saying that the friend will sleep with him if the photo gets one million “likes” on Facebook. (Kverneng later told media outlets the photo was a joke.)

Though both photos skyrocketed in popularity, the pattern of sharing was quite different between the two. The Obama photo was reshared more than 618,000 times, and generated nearly 7.4 million “likes” and more than 574,000 comments. Most reposts of that photo came from people that were already subscribed to Barack Obama’s Facebook page. In the case of the Norwegian man’s photo (150,000 reshares, 1.8 million “likes,” 152,000 comments), the growth curve was more “organic”; people found the photo when friends shared it, then shared it to their friends, and so on. The feeling of participation -- contributing toward the goal of one million likes -- may have fueled the spread as well.

In both cases, the rise in popularity was meteoric and sudden, with 90 percent or more of the shares occurring within the first 24 hours of the photo’s initial posting. The Obama photo tapered off in popularity, with a smaller resurgence of reshares around Valentine's day. Kverneng made his meme private shortly after he reached his goal of a million likes, according to the paper.

The authors -- P. Alex Dow, Lada Adamic, and Adrien Friggeri -- say their findings "suggest not only that [sharing] cascades can achieve considerable size but that they can do so in distinct ways."