i had a school project a few years ago on this dude, mansa musa. the guy practically doesn't exist. there were maybe 3 books that had about a paragraph about him, and a childrens book that mentioned his name once. the internet didn't help, all the information conflicted with itself, like birth year, differen't dates, and who his father was. i asked the librarians, 3 of them. they looked and looked, and found nothing (using google like i had already done). i failed the assignment because the teacher was an *** and gave me a person that no one knows anything about.
anyways, that story shows that the above poster is right, now, or in a few years from now, librarians wont be any more helpful than you googling what you want to know.