Improvements on the word strength algorithm.
I just noticed today some improvements on the algorithm that keeps record of which words were practiced (and therefore strengthened ) after each lesson or practice session. It used to be that only words belonging to the vocabulary of the unit that the lesson or the practice session belongs were strengthened. As a result there were many words that I would see almost every day, and yet in my vocabulary they were considered weak.
Today I noticed that when doing a practice or lesson from one unit, words from other units are also strengthened, which makes much more sense, since the separation of the vocabulary is a mater of definition, and it does not affect much the way words are stored in our memory.