What I've been reading online talks a lot about liability, insurance, and other issues that I do not foresee being relevant to running a website, but it sounds like an LLC mitigates those issues. It will cost me a few hundred dollars and quite a bit of time to set up an LLC... I could always start as a sole proprietor and then make the switch if I deem it necessary, so that's the option I'm leaning most towards.
I know plenty of folks on here have hobbies and small businesses or websites they try to monetize, so maybe you have an idea I haven't considered?