Blog Post
Hello Dave,
The breadth of knowledge and breadth of their audience are indeed important, but they are more suited for influence that are not social media (ie, offline influence). We can certainly put them in a social media context, but if that is the case, then I would argue that both of the factors you mentioned are subsummed in the 6 factors already.
1. Breadth of audience is essentially a social equity metric (see Finding the Influencers), and it is a measure of his bandwidth. Bandwidth as defined in this article would include his network, audience, reach, etc.
2. The breadth of knowledge, the fact that he is generally intelligent, humorous, well spoken, etc., essentially gives the target more confidence, which is also a factor that we will cover this week. In fact Your example of Stephen Fry is an example of a respected authority figure that the targets trust. This will be discusee in the last article of this miniseries.
The next 2 articles of this miniseries is already out. The last one will be posted sometime later this week.
Thanks again for the comment.