Selenium is a technology used to test web sites by firing up a browser and then interacting with a web site. It can be used from a number of languages - Java, Python, Ruby. Scalatest 2.0 introduced a DSL which simplifies the writing of tests in Selenium. More importantly, it simplifies the process of reading and understanding the tests. It becomes easier to walk through a test with a semi-technical person.
Clipping is a handy way to collect important slides you want to go back to later.