What does a hedge fund do?

Ever wondered what a Hedge Fund does? I thought that the top voted answer in this Quora question was a great explanation.

(Note: when you go to the site it might ask you to sign in. There is an option "close and read first answer" that you can click so you don't need to sign in to read the answer.)
None of the answers discussed the role that Hedge Funds play in Shadow Banking where their participation makes up a large portion of the SB Industry. You can search ZH for more on this.

BTW if anyone knows of a good article explaining Shadow Banking in a way that won't make your brain bleed reading it please lemme know.