Question by Dominik: What is Selenium ? And how is it used in web application testing? Do you have to code in Selenium?

Best answer:

Answer by Chris G
Selenium is a framework to automate front-end tests. It’s used to cover those parts of an application that can’t be covered by simple unit testing.

There’s an intro here: http://seleniumhq.org/movies/intro.mov

Know better? Leave your own answer in the comments!