Pursuing the “big influencers” alone is probably one of the biggest fallacies on the Web.
Put aside the challenge of how to find influencers and let’s consider what “influencer” means. To me, it’s someone who has earned ongoing attention of an audience or community and can motivate others to action. There’s often a disconnect between the appearance of influence and those in a position to act on it.
Mass influence exists, but it’s often confused with popularity. They’re not the same thing.
Influencers with mass appeal are easy to find and get found often. They get pummeled with requests by others to do things: share this, promote that. Some of them take up those offers and lose credibility by over-promoting. While they have a significant community watching and listening to them, the ability to inspire action is often lost.