Ad.ly is an ad network for Twitter, but also offers an analytics service, via a partnership with PeopleBrowser, that is quite a nice tool. It analyzes both your content and audience, all after you log in via oAuth.
Here are some of the features:
- When you tweet compared to when you get retweeted
- Map overlay of followers
- some basic demographics
- how engaged they are
- your most influential followers
Now for the pitches. They have some buttons to get you to advertise in your Twitter stream and also the ability to buy the advanced analyze report for a mere $9.99. Once again third party developers are monetizing, but not Twitter.
Luckily most of my followers are engaged and have not been identified as bots, abandoned, suspended or following too many people.