Who Does Exploratory Testing?

Any software tester knowingly or unknowingly does it! While testing, if a tester comes across a bug, as a general practice, tester registers that bug with the programmer. Along with registering the bug, tester also tries to make it sure that he/she has understood the scenario and functionality properly and can reproduce the bug condition. Once programmer fixes the bug, tester runs a test case with the same scenario replication in which the bug had occurred previously. If tester finds that the bug is fixed, he/she again tries to find out if the fix can handle any such same type of scenario with different inputs. For an example, lets consider that a tester finds a bug related to an input text field on a form, where the field is supposed to accept any digit other than the digits from 1 to 100, which it fails to and accepts the number 100. Tester logs this bug to the programmer and now is waiting for the fix. Once programmer fixes the bug, it sends it across to the tester so as to get it tested. Tester now will try to test the bug with same input value (100: as he/she had found that this condition causes application to fail) in the field. If application rejects the number (100) entered by the tester, he/she can safely close the defect. Now, along with the above given test input value, which had revealed the bug, tester tries to check if there is any other value from this set (0 to 100), which can cause the application to fail. He/she may try to enter values from 0 to 100, or may be some characters or a combination of character and numbers in any order. All these test cases are thought by the tester as a variation of the type of value he/she had entered previously and represent only one test scenario. This testing is called exploratory testing, as the tester tried to explore and find out the possibility of revealing a bug by using any possible way. What qualities I need to posses to be able to perform an Exploratory Testing? As I mentioned above, any software tester can perform exploratory testing. The only limit to the extent to which you can perform exploratory testing is your imagination and creativity, more you can think of ways to explore, understand the software, more test cases you will be able write and execute simultaneously.