I took it to mean that most developers in this current market do not need to know implementation perfect algorithms and data structures like RB trees, depth first search, A*, quicksort, etc. Rather your time is better spent on learning the advantages and disadvantages on the structures and algorithms, and you get more benefit from understanding the implementation. For example, merge sort is dividing a list up into sublists until you hit single element lists and recombine them into a single sorted list. That, in my opinion, is more important than a picture perfect implementation on a white board.