We’ve seen a lot of recent examples of consumer web services and content which have taken off with viral adoption. While my perspective is that people over-use the term “viral”, it’s obvious that success cases are tremendous.

I’ve been thinking a bit recently about what truly makes an online service/service viral, and I’ve come to a (very preliminary) conclusion that it rests on three variables:

1. How inherently sharable it is. If people like what they see or do, they’re going to want to communicate about it to others.

2. How easily sharable it is. I’ve written before that friction is multiplicative – it’s important to reduce friction before and after desire actions because conversation rates in a several step process multiply across the entire sequence as a whole. Therefore, the simpler it is to share a content or service (which includes the messaging about the steps, as well as the difficulty of the steps themselves), the better.

3. How integrated the sharing is into the content or the service. The more deeply imbedded the act of referring is into the product the product or service itself, the more natural is becomes to share it, as the user spreads recommendations simply by using the service or content itself. (I’ve talked more about this notion here).

Perhaps these three components themselves are multiplicative? Dare I suggest a theoretical equation to summarize/articulate?

Viral adoption = (how inherently sharable x how easily sharable) x (integration of sharing into content/service)

My ideas about these issues were brought to mind today when I read a great piece from Marketing Sherpa, “Viral Marketing Hall of Fame 2006: Top 12 Campaigns You Should Swipe Ideas From.” It lists and then goes into great detail about a dozen highly successful recent viral campaigns and the lessons to be learned from them. While some of the recommendations are obvious (“blogs are now the seed campaign of choice”), there are some very insightful remarks about presentation of, patience with, and predictions about online viral marketing. Anyone with a hand in or an interest in marketing online services with a viral component should definitely read the entire piece.