Exploratory testing belongs in Quadrant 3 of the Agile Testing Quadrants – Business facing tests that critique the product. You can see more about the quadrants in Brian Marick’s blog “My Agile Testing Project,” http://www.exampler.com/old-blog/2003/08/21/ or in our book “Agile Testing: A Practical Guide for Testers and Agile Teams”.
I guess the first time I heard about it, was at the Canadian Agile Networks workshop in 2005. At that time, I was very interested in the cultural aspect of agile. Jonathan Kohl’s position paper was Exploratory Testing using personas, which can be seen here http://www.kohl.ca/blog/archives/000095.html. Since then, other people have touched on it as well. For example, Elisabeth Hendrickson in her presentation http://www.slideshare.net/codecentric/exploratory-testing-inagileoverviewmeettheexpertselisabethhendrickson
I understood personas much better after listening to people like Jeff Patton and David Hussman. Read up on Jeff Patton’s website- http://www.agileproductdesign.com/blog/agile_product_development.html
Using personas is a great way to help identify requirements but they can also help us test better. When I use personas to help identify test data and test scenarios that I (as a tester) had not thought about before, it helps me get better test coverage. To do this, I need to understand our customers – both internal and external. The marketing folks are often the ones who create the external personas, but sometimes overlook internal customers like administrators.