In his paper, "Exploratory Testing Explained", Bach says exploratory testing is misunderstood and abused as just putzing around with no real plan in mind. Yet, he claims it can be way more productive than scripted testing. Perhaps.
I think this paragraph sums it up:
Exploratory testing is also known as ad hoc testing. Unfortunately, ad hoc is too often synonymous with sloppy and careless work. So, in the early 1990s a group of test methodologists (now calling themselves the Context-Driven School) began using the term “exploratory”, instead. With this new terminology, first published by Cem Kaner in his book "Testing Computer Software", they sought to emphasize the dominant thought process involved in unscripted testing, and to begin to develop the practice into a teachable discipline.
Exploratory testing is simultaneous learning, test design, and test execution.
This is a general lesson about puzzles: the puzzle changes the puzzling. The specifics of the puzzle, as they emerge through the process of solving that puzzle, affect our tactics for solving it. This truth is at the heart of any exploratory investigation, be it for testing,development, or even scientific research or detective work.
The external structure of ET is easy enough to describe. Over a period of time, a testerinteracts with a product to fulfill a testing mission, and reporting results. There you have the basic external elements of ET: time, tester, product, mission, and reporting. The mission is fulfilled through a continuous cycle of aligning ourselves to the mission, conceiving questions about the product that if answered would also allow us to satisfy our mission, designing tests to answer those questions, and executing tests to get the answers