Calculating combinatorial explosion: a tool for word of mouth marketing

I am not a big fan of the term 'viral marketing':  the swine flu pandemic (or H1N1 for those who think pigs are being unfairly singled out) has certainly reminded us that 'viral' things haven't historically been perceived positively...especially by those who are infected.  And yet, some in marketing and PR circles continue to let the term fly when discussing why social media should matter.

Word of mouth, on the other hand, seems to focus more explicitly on all that is wunderbar with social media. Influencers tell influencers who tell influencers...and so on and so on...and when it's digital, it's free!

Of course, when everyone is an influencer at some level, marketers might wonder just how many influencers it takes to get a critical mass of pass-alongers. One tool to help in the planning stages uses simple factorial math to calculate the reach that a viral word of mouth approach might achieve.

I've posted a simple spreadsheet version of the tool you can download on the Dialogue Marketing website, here. (MS Excel file)

The idea is relatively straightforward: capture a few assumptions and see how many people you might actually reach.

The assumptions in the tool include:

1. Number of initial influencers (or seeds) the campaign will contact
2. Expected pass along (i.e., retweet, email, linkback) percentage
3. Number of  people these influencers will reach
4. The number of pass along cycles (the 'and so on' part)

By structuring the capture of assumptions, enabling easy development of goal scenarios, and keeping the math in the background, the tool provides campaign planners with an easy to use expectation setter.

Try it out and let me know what you think.