At Functional Scala, Karl Brodowsky based his talk on combining algorthms with functional scala, he begins by listing what he considers 'dangerous', he then moves on to immutability and helpfully shares some examples of where it might be used. Just in case you were wondering - he also considers why. His talk ends discussing sorting - how to make it more efficient and parallel sorting.
This talk was given by Karl Brodowsky at Functional Scala.