Fatwas are rulings by Islamic scholars on various parts of Sharia. They run the gamut from ancient to modern and all scholars of Islam may interpret various parts of the Koran and other primary sources in creation of fatwas. I'd assume that scholarly reputation has a lot to do with how a fatwa by a given author is received.

Unlike anything I've seen in my limited look into Christianity, fatwas attempt to answer specific questions -- What do I do if my husband forces me to drink wine? or Should all Muslim men wear a beard?