The key flaw in the arguments about user actions driving better search discovery is that not everybody is willing to contribute an action.  A click on a link is enough to create some interesting discovery effects, but much better than that is qualitative effects of ratings, tags, comments, blog posts, etc.  As Steve Goldstein and Clare Hart noted, "People are busy."

I've been waiting for someone to put some kind of number out there that helps clarify why a segment of a community can influence the perspective of the whole in important and relevant ways through their participation.  Finally, a model emerges from Yahoo!'s Bradley Horowitz with his second post on his new blog.



He explains how this ecosystem defines the community and creates the opportunities that drive better discovery:

"There are a couple of interesting points worth noting.  The first is that we don’t need to convert 100% of the audience into “active” participants to have a thriving product that benefits tens of millions of users.  In fact, there are many reasons why you wouldn’t want to do this.  The hurdles that users cross as they transition from lurkers to synthesizers to creators are also filters that can eliminate noise from signal."

This is what drives the ability to bubble up tail content in meaningful ways.  It's all about user actions.