For me, they are the social catalysts, partly (but not entirely similar) to those people mentioned in Malcolm Gladwell's Tipping Point book.
Note: I actually disagree with his definition that only specific people are responsible for causing sways in opinion, buying patterns and trust. Instead I think that these people could be anyone, even potentially collections of people. However as I've mentioned before, surely the interesting bit is the 'who' and 'why'.
So what exactly do they influence? Well, assuming they are all talking about their effect on your company, then these people will all apply different actions or factors to your Corporate Social Graph.
Here's my suggestions on what some of those influences could be:
- Influencing sentiment
They have an emotional opinion about your company (and the secondary effect of telling others). This sentiment could either be positive or negative and can have an indirect affect on your company.
Examples: Brand advocates
- Influencing behaviour
They have an effect on the sales or take-up (negative or positive) of your products/service. This therefore directly affects your revenue (& profits).
- Influencing links
Assuming you already have a website, then links to your site will improve your positons in the key search engines (e.g. Google). What's more, these links can still positively contribute to your SEO efforts, even if the sentiment or behaviour they create isn't.
Proof that there is only one thing worse than being talked about and that's not being talked about.