Looks like a Firebug for IE 6+.
"MySpace’s Performance Tracker is a browser plugin that help developers to improve their code performance by capturing and measuring possible bottlenecks on their web pages."

"We will publish articles relating to HTML5 and it’s semantics and how to use them, here and now. We will also be inviting questions, in the form of ‘Ask the doctor’ to help answer people’s queries and questions. Answers will be posted in the form of articles for all to learn from."