ImpactWatch is one of our main products. It is a PR measurement tool that our clients use for mainstream media coverage, but blogosphere measurement is harder to assess since readership and authority aren’t easily quantifiable.

Companies simply lack the resources to closely monitor all that is said about them, and blogs have expanded their radar screen. I don’t know if the blogosphere has increased the number of people who chit chat about a company with others, but it has created a forum in which many more voices are measurable.

However, not all voices are equal in their importance to a company. Concerning this fact, one of issues I’ve grappled with is how to weigh general influence and influence within a specific topic.

For instance, using Dell as an example, most of the A-list bloggers very rarely discuss the company and its products directly. Granted, top blogs like Engadget and Techcrunch should interest Dell since they focus on technology, but what about other blogs like Boing Boing and The Huffington Post?

I use Dell as an example since the company has had to deal with a top blog that doesn’t focus on its arena. Remember Dell Hell?

Although Jeff Jarvis and his BuzzMachine blog are prominent, they focus on media, not technology. Thus, they typically shouldn’t worry Dell, but when Jarvis blogged about his “Dell Hell,” the rules changed. In fact, sometimes when bloggers (especially an A-lister) complain about a company and its products, word can spread fast. Sometimes even the mainstream media picks up on such rants.

Measurement is tough in situations like Dell Hell. Does Dell need to devote resources to scrupulously follow BuzzMachine? No, since Jarvis mainly blogs about media and not computer hardware and software. However, Jarvis was worth Dell’s attention for a while.

How can a company determine which bloggers who don’t focus on the company and its field require their attention? Then, when should they start and stop monitoring such blogs?