I think they've added components since I ran this, but the site is down today so I'll go with what I've got.
Audience measures how people respond to your posts. It's not just how many followers you have but how many people pay attention to what you're saying. Basically this reduces the effect of being followed by spam bots. They also claim it accounts for the relative size of your audience compared to the rest of the community.
Activity measures the amount of relevant content posted about a topic area. Basically this accounts for the people who stop paying attention to you because you tweet too much or too little about the topic of interest to a given community. This is also a community-relative score. So if you're party of a highly active community around a topic, you'll need a higher level of activity to score higher.
Authority measures reliability and trust. That's basically how much your followers can rely on your recommendations and opinions on a given topic. They calculate authority around eight benchmark topics. These topics are also shown in the topic fingerprint diagram.
The benchmark topics are (clockwise from top of the diagram):
AME - arts, media and entertainment
TEC - technology and the Internet
SCI - science and the environment
MED - health and medical
LIF - leisure and lifestyle
SPO - sports
POL - news, politics and society
BIZ - finance, business and economics
With all that said, I really don't know what to make of my scores. The biggest surprise to me is my topic footprint. I would have expected more authority in science and environment, given that I tweet about piping plovers and beach ecology a lot of the time. Technology and business seem about right. I can't remember ever tweeting about politics, so have no idea how I got any footprint in there at all. As for arts, media, and entertainment, unless they count soup as entertainment, that one's a mystery too.
So what does all this tell me about the real world in which I write technical documentation, develop New England day trip travel content, and talk to people about piping plovers?
Certainly in the piping plover sphere, I have way more influence when I'm standing on the beach with the USFWS logo on my hat and shirt and talk to people one on one about how cute piping plovers are and what we're doing to save them and why people should pay attention to laws and regulations. The three-year-olds that I'm telling not to disturb the baby birds are not following my tweets, nor for the most part are their parents. Maybe one or two of the striper fishermen are, for news purposes.
As far as New England day trips, I don't tweet much about what I'm doing with New England Day Trips at Hand. What would I tweet about it that would increase my credibility as a travel writer/content developer/photographer?
As for technical communications, since it's a relative score, much of what I have to say about how to do #techcomm, has already been said a thousand and one times. Again, much, if not all, of my influence is and has been live and in person in the workplace. Getting the same level of street cred in the social media sphere as I've had in the real world is going to take awhile. Meanwhile, I've got stuff to do, places to be, and people to see.