Machine learning is teaching the computer how to learn by itself. It is far easier to be done, especially when you have small data set and a good level of expertise in your field. Classifying objects, predicting who will buy, spotting comments in code is achieved with grassy algorithms like neural networks, genetic algorithms or ant herding. PHP is in good position to make use of such teachings, and take advantages of related technologies like fann. By the end of the session, you'll know where you want to try it.