It's a good time to be a horror fan right now.
1. /r/nosleep on Reddit: the Internet’s Necronomicon
Reddit works on the idea that you vote on the stories you read - the numbers circled in yellow. If you like a story (and have a user account - yes, it's free), then upvote - this is how other users show you what they enjoyed. Didn't like the story? There's a downvote button. In this way, Reddit's algorithms can find the cream of the crop.
There are three main tabs that you'll find most useful. The first tab you encounter - the HOT page, is a mixture of today's popular stories, and a few new ones. The NEW tab shows you … you know what? I reckon you can work that out. The TOP is a list of the most popular stories of all time in /r/nosleep.
Keep an eye out for the series (they should be marked as such!) - these'll hook you for hours. Don't start reading one of those just before bed … if nothing else, you'll want to carry on reading. You can even get some free ebooks, if you look hard enough.
As with all articles on Reddit, there is a comments section. Quick heads-up on the one rule for commenting: treat everything you read as absolutely true. Even if you're sure it isn't: suspend your disbelief. Trust me; you'll enjoy it more that way.
Here are a few of my favourites to get you started:
The Minimalist by urban_teller: What do you really need to be happy? Money? A car? A roof over your head? Clothes? Or maybe even less than that?
The Spire in the Woods by TheBoyInTheClock. This is first of a series: a group of (sorta) friends investigate the suicide of one of their classmates in New England.
The Midnight Game… by [unknown]. You know those games you shied away from playing as a child? Mirror watching, Ouija boards, séances? Yeah, you were right to.
Penpal by 1000Vultures. Probably the most-read story on the entire site. The author actually got this one published!
Bonus! Not much time? There is a subreddit for you: /r/shortscarystories. Navigation works just like /r/nosleep.