Is it possible to guess a user's mood based on the structure of text?

Question

I assume a natural language processor would need to be used to parse the text itself, but what suggestions do you have for an algorithm to detect a user\'s mood based on tex

Answer 1

I think, my algorythm is rather straightforward, yet, why not calculating smilics through the text :) vs :(

Obviously, the text ":) :) :) :)" resolves to a happy user, while ":( :( :(" will surely resolve to a sad one. Enjoy!