What is different about Agile Testing

As per Wikipedia, Agile testing is a software testing practice that follows the principles of agile software development. The Agile implementation may not be successful, if the traditional testing practices are continued in Agile. So, it is important to know why testing in agile need to be done differently. 

Requirements (Stories) not cast in stone: Requirements in Agile are not elaborated to the minutest details (as in traditional BRD documents). The requirements are in the form of Stories in User's voice stating who is user, what he/she wants and why. The implementation of the story is negotiable and may change as per the discussions between Product owner and the team. Tester's role is important here to make sure that all possible workflows have been considered and there is no ambiguity or missing requirement. 

Testing is not a phase: Agile teams don't wait till end of the release cycle to test, rather they test throughout the release cycle. Testing is part of Define, Build & Test (DBT) cycle and all these activities may be performed multiple times for a single story in a sprint. 

Developers and Testers are not adversaries: In the traditional environment, the adversarial relation between Developers and Testers is encouraged, so that Management gets insight about product quality from an independent source. This needs to change in Agile with both developers and testers working towards quality and timely release. 

Testers are not Gatekeeper of quality: Quality is everyone's responsibility. Testers collaborate with Developers to find the bugs as early in the cycle as possible. Testers's job is to provide information regarding quality to the team. The boundary between Developer and Tester is getting thinner. Their roles may overlap - Developers may test and Testers may code as the situation demands. In some teams, all team members perform role of both tester and developer. 

Test Automation: There is not enough time to perform extensive regression testing at the end of the release cycle. So, there is increased emphasis on Test Automation. The test automation needs to be planned properly. Test automation does not mean only functional or end-to-end test automation. The test strategy should consider Unit, Integration/ component tests as well.

Let me know if you disagree on any of the above points or if you like to add any other important difference.