Literally any thing that isn't trained on blogspam or notorious for making up shit. You're basically using a magic 8-ball to "learn" it just repeats what you say back at you. Its useless for research.
I think people are overly critical - it is alright for some things, and it has gotten things right for me before, but generally I have to spend so much time double checking that it's right that it isn't worth the time. If it gets a detail wrong 10-15% of the time, then I have to check it every time.