Great points and thanks for your comments on this subject.

I think that it's a great idea to look at the audience based on the individual. If I'm understanding you, you're suggesting that the difference between an influencer and an evangelist is the audience associated with each role?

There are definitely other factors that differentiate between these two sides besides just simply the fact of bias. The amount of engagement, the tactics, the sharing, communicating, etc all play a factor in the whole scheme of things.

However, I disagree with you on the fact that marketers like influencers. These are the guys that would like both the influencer and the evangelist/champion. The latter will definitely be in favor of the product – making the marketer's work a success and them being happy. The influencer is a wild card but if they are doing a good job at marketing the product, then it can work in favor of the marketer. Perhaps this is also a wild card for those in PR?

You can also use the indiividual's audience, as well as position, to distinguish between different kinds of influencers and evangelists. These obviously aren't descriptions of people (a person has influence among certain audience about something — but isn't just an all around influential type of person in all aspects, and isn't a person who wakes up thinking about influencing people). If we view influence as something measured by impact w/in the individual's audience, we shift from attributing influence to the acts of the influencer over to the responses of the audience. Which seems more accurate, since we know that influence is contingent on audience response (and influencers lose influence as soon as their audience walks away).

By defining it as a relation between the influencer or evangelist and the audience, we can now see more clearly that it's engagement strategies and tactics, ways of sharing, communicating, recommending, and interacting that may qualify differences between influencers and evangelists (and really, these should be subdivided into core activities probably so that we dont think of them as people archetypes. Evangelists may have deep passion for a brand, but if they don't interact with an audience that shares this passion and which views the evangelist either as an expert, a popular person, a news maker, etc, then the evangelist has no tribe…)

Marketers like the influencer – aspirational relationship as one that can make buzz, for example. But there are others — that involve viral sharing, or expert recommendations, etc. You know where i would go with that: social dynamics and kinds of populations and interactions that might be good for a brand.

cheers
adrian