I think there's a bit of a convergent evolution

House Of Leaves is similiar to Backrooms in a way - they represent the same kinds of horror but it's more like how Weird Fiction converged and inspired in the same way. There's a level of early slenderman there as well (in terms of a lot of the early slenderman horror being more about the horror of dreaming this entity into the real)

I'd argue SCP Foundation is probably one of the main initial examples of internet occult, the Backrooms have more in common with a few SCPs.

To go wider there's probably a convergent horror - It's the classic aspect of horror stories of the age represent subliminal fears of the age (e.g, bloodsucking vampires mean very different things across the past thousand years). I think liminal horror is a representation of a lot of our fears, so multiple different effective horrors have converged on these feelings of discomfort with spaces.

I'm not really smart enough to know what it means - probably something about modern society dissassociating people from the space, but don't know much more.

> I'm not really smart enough to know what it means - probably something about modern society dissassociating people from the space, but don't know much more.

I think it has something to do with the controlled comfort of modern life. And how even a small disruption can become unsettling.

Like in HoL, the most chilling scene isn't anything that happens beyond the door imo. It's when the book falls because the house changed size ever so slightly. I think the classic haunted house trope is at play there too - home is comfort but those stories frequently involve a move, which is inherently stressful. I remember when I bought my house..every new noise or small change was disturbing. Potentially a hidden horror lurking in the house (like a water leak).

House Of Leaves was published in 2000 and Backrooms originates (as far as I can tell) from like 2011? Not that it's impossible that the ideas developed independently, but given how big a cult hit House of Leaves was I'd be very surprised if there wasn't some direct lineage. Not trying to gatekeep, it's just that the Backroom trailer was giving me _really distinct_ HoL vibes. I wonder if that's just the film mixing in ideas that weren't necessarily present in the original copypasta.

edit: Another thing I will say is that I've noticed both HoL and Backrooms seem to act like a kind of shibboleth for a particular demographic (not even really the same demographic) and you often see this in how people write/talk about both. I think it maybe stems from how dense/unapproachable the two works are, how innocuous they seem on the surface such that you really have to sink some effort to get at them.