WebDriver randomizing data is an idea where we want to ran the same test using randomly generated data. Using randomized test data for a test can bring to light test failures which otherwise may have passed. When randomizing data in a test your test scenario does not change but the data used for the test will and this may result in errors which you might have otherwise not know about.
WebDriver Randomizing Data Video Tutorial
Using randomized data can be a great way of uncovering bugs and defects in your code base whilst still ensuring that the scenario which you are testing is covered by your tests.