Zarrella’s Hierarchy of Contagiousness

Posted on Mar 18th, 2010

If you’re familiar with Maslow’s hierarchy of needs, the title of this post will ring a bell.

I first began to formulate this framework as a model for understanding how ReTweets work (If you’re interested in my Science of ReTweets study, check out my live webinar Friday). But I think the concept extends far beond just Twitter in fact, it is a framework for understanding criteria required for an individual to share any kind of content. Each of these criteria has a corresponding action we as marketers can take to increase the contagiousness of our content and ideas.

As you can see there are three criteria and together they form a funnel of decreasing volumes, like a sales conversion rate funnel.

  1. A person must be exposed to your content to ever have a chance of spreading it. This means they have to be following you on Twitter, fans of your page on Facebook, on your email list etc.
  2. The person must become aware of your specific piece of content before they can spread it. They have to read your Tweet or open your email.
  3. That person must be motivated by something (generally in the content itself) to want to share it with their contacts.

Every piece of content, social network and campaign has vastly different conversion rates at each step of this process but, to understand the scales involved, it helps to visualize a hypothetical set of percentages. The gray boxes on the left of the graphic above represent assumed numbers: if you email 900 people and 20% of them notice and open the email and then 10% of those readers are forward it to a friend, your email was shared 18 times.

At each step we can change the numbers in our favor:

  1. Increase the number of people exposed to your content by building your reach. Get more email subscribers or Twitter followers.
  2. Create attention grabbing content. Do lots of testing on your subject lines to increase open rates.
  3. Include powerful viral calls to action.

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View Comments to “Zarrella’s Hierarchy of Contagiousness”

  1. richardlebovitz Says:

    Doesn't the viral nature of social media assume one to many exponential growth? Your schematic instead shows diminishing growth, arguing that growth isn't a given in a social meeting campaign, at least not from the starting point you describe. If this is the way social media works, instead of the conventional view, then maybe the starting point is not the 900 but the 18 who redistribute the information to their friends, who then in turn redistribute to their friends, and so on. Or am I missing something in your illustration?

  2. Dan Zarrella Says:

    Richard,
    I assume you read my post, what did I say the graph showed?

  3. richardlebovitz Says:

    The graphic shows the conversion rate for a piece of content delivered via Twitter or email, and that this rate diminishes more or less based on the three criteria you describe. That much I understand. What I'm saying is that most people view social media as a way to expand reach, whereas your model shows a contraction. While what those initial 900 and the next 180 are a concern, I'm curious about those remaining 18 and where they fit into the equation, in other words, how do we leverage that initial 900 into, say, 1,800. I believe you've already answered that question as it relates to “content,” “relevancy” and “call to action.”

  4. Dan Zarrella Says:

    If 900 people see your content, maybe 18 will share it with others.

  5. ckwrites2 Says:

    marvelous adaptation of the classic sales funnel, or as I like to call it the social media marketing funnel – interesting to see that self selection and relevance remain the driving forces. wondering Dan if this also relates to the very brief half life of a tweet and even more so a retweet?

  6. Nathan Clendenin Says:

    I would assume the graph above can be applied again with each of the 18 people who retweet your content to their followers (exposure). While the 18 are indeed increasing your exposure, the contagiousness is always diminishing. But if somebody with tons of followers and clout retweets you then your exposure goes up again and instead of 18 you have like 200 people retweeting and the virus starts spreading…

    I'm pulling this out of my arse, but maybe you can think of it like riding a bicycle. As you peddle, you move forward. Without more peddling you coast to a stop. Your forward movement represents your contagiousness. It's always fighting gravity and friction to stop. If your exposure is low, it's like your not peddling. If your awareness or motivation are low then it's like you're going uphill. If your exposure is good then you're peddling hard and if you're awareness and motivation are great you're also on a downhill picking up speed!

    Not sure if that analogy works or is even accurate, but it was helpful to me. This stuff is fascinating to learn about.

  7. KINGRPG Says:

    I like that you think. Thank you for share very much.

  8. Electronic Cigarette Girl Says:

    Ill be developing my fb and myspace profiles based on this and will know if it works or not haha jk. Im sure its great advice, I just have to apply it.

    -Bella :)

  9. tim diaz Says:

    Very creative Dan! Just a fun fact, if you ever need a yacht or boat shipped anywhere, Yacht Exports is your best bet. They have done a great job with me!

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  12. Vincent Says:

    Hi Dan,
    I'm with some of Richard's comments on this one. Maybe it's the choice of word; contagiousness

    18 out of 900 doesn't sound very contagious, certainly not in the 'viral' world?

  13. John Haydon Says:

    Dan – I'm really curious about this model you've created (it's a very novel idea… ;-) ), and I especially like your point of changing numbers in our favor.

  14. John Haydon Says:

    The point of this post is to outline a framework for how content spreads online. Dan assumes that we can plug in our own numbers.

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