What is special about the kNN algorithm? What are the advantages and disadvantages of kNN as compared to ANN and SVM? What are the critical success factors for a kNN implementation? What is a...

What is special about the kNN algorithm? What are the advantages and disadvantages of kNN as compared to ANN and SVM? What are the critical success factors for a kNN implementation? What is a similarity (or distance measure)? How can it be applied to both numerical and nominal valued variables?