Alphabet Magnets

For Christmas, Christopher got a set of alphabet magnets in his stocking. He is very into letters and numbers right now. When we first put the magnets on the fridge, he saw them, he looked at them and said, "words!" Then last night, I was watching TV and he came into the living room holding one of the magnet letters, he put in my hand and said, "B." I looked down at the letter and it was the "B." I was very surprised. I would normally think it was just a fluke or coincidence but then he repeated it with the "A" and "J." When did my 2 year old son start learning the differences between the letters? The only thing I can think of is the Blue's Clues video we bought him called Alphabet Power. I never thought that my two year old would be learning the alphabet. I didn't think that we would be working on that until he was a little older. Apparently I'm little behind and my son is teaching me a thing or two.