I’ve written several times about my experiences launching and growing a networking group (Online Lead Generation) on LinkedIn. What started with 60 friends in the lead gen industry in March 2008 is now a 4500 member, worldwide group, apparently one of the 1% largest LinkedIn groups on the planet.

My assumption about the growth of this group has been that it would see “hockey-stick” growth. In other words, membership would grow slowly at first until there was a critical mass of members, at which point the virality (network effects) of the group would kick in and I’d see a huge spike in weekly membership requests.

And this is what I anecdotally observed to be happening – it seemed that the number of applications was increasing each week. Well, nerd that I am, I decided that to really assess the growth curve, I had to get some real numbers in front of me. To wit, I downloaded an Excel sheet of the date of every member’s admittance to the group and then created a graph showing the progression of growth. Here’s the chart:

As you can see from this chart, the slope of growth is basically constant. There is a slight uptick about three months after inception, and then a significant uptick in mid-December, but beyond that, the growth is very constant. Moreover, I believe the growth that has been achieved in the last month is not organic but rather the result of global changes within LinkedIn (specifically, LinkedIn has started to include a list of “recommended groups” when you login to one of your group pages). So other than a bump right after the first three months of existence, the growth has been steady ever since.

This really surprises me. I’ve always assumed that viral growth was exponential in nature. I’m not a viral marketing expert, but perhaps this suggests that there are different types of virality – some steady and some exponential. I’d be curious to hear the opinion of experts in the space.


  1. Red Lebster January 26th, 2009

    I think your theory is half right. LinkedIn Groups, to me, are only half viral. Most viral apps rely on universal appeal (the original hotmail) and some sort of incentive to encourage referrals (zombie wars on Facebook) to kick growth into high gear. In the case of LinkedIn Groups, the appeal of a specific group is typically narrow, there is no simple-to-execute mechanism for referrals, and (if you don’t log in regularly) you won’t see that people in your network have joined groups in your news feed. To me, these are highly limiting factors for LinkedIn virality.

  2. David Rodnitzky January 26th, 2009

    I think that is a valid observation, Red Lebster, but even if there are limiting factors on LinkedIn, wouldn’t you still expect the growth rate to be somewhat exponential? I mean, if only 5% of LinkedIn users login regularly, you would expect exponential growth, but at 5% of the potential growth.

  3. emilia November 13th, 2010

    really like your blog! greets from Poland :)

  4. Tayler February 16th, 2012

    It seems to me that “viral growth”, by definition, just means a viral co-efficient < 1. Anything less than that and it's just called "growth"

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David Rodnitzky
David Rodnitzky is founder and CEO of 3Q Digital (formerly PPC Associates), a position he has held since the Company's inception in 2008. Prior to 3Q Digital, he held senior marketing roles at several Internet companies, including Rentals.com (2000-2001), FindLaw (2001-2004), Adteractive (2004-2006), and Mercantila (2007-2008). David currently serves on advisory boards for several companies, including Marin Software, MediaBoost, Mediacause, and a stealth travel start-up. David is a regular speaker at major digital marketing conferences and has contributed to numerous influential publications, including Venture Capital Journal, CNN Radio, Newsweek, Advertising Age, and NPR's Marketplace. David has a B.A. with honors from the University of Chicago and a J.D. with honors from the University of Iowa. In his spare time, David enjoys salmon fishing, hiking, spending time with his family, and watching the Iowa Hawkeyes, not necessarily in that order.