And then another woman, looking melancholy, walks through the door.

She pauses when she enters, seeming confused, glancing around.

She looks up. 

Aside from the bar, this is the first other person she's seen here, and the first person she's seen from another world. 

No neuropotential, not even a wisp or a remnant. Nor a rechanneling. Otherwise she reads in fact like the familiar sort of person. Not connected into anything, not under influence. (Not anything like a representative sample, one person - of anything let alone of everything. But it is information.)

"This is an interdimensional bar appropriating doors from other locations," she says out loud. "Sells non-magical objects and food; lends books. Stops time at your origin."

"You know I'm here?"

She can easily think of circumstances that would lead to someone being surprised by this. Cannot so easily think of circumstances that would lead to the question making sense to ask, but given how much variety in worlds there appears to be, this is quite likely to be a failure of her imagination.

Or the entrant could just be expressing the surprise.

"Yes. You walked in" - she gives the span of time - "ago". You're standing near the door. You're -" she describes the entrant's appearance as she sees it.

" - People usually can't remember anything about me, not for very long."

"...I'm not certain if the location would protect against that. You could ask.

If I create a record or reminder on my device, would that cause me to forget it exists, or cause other side effects?"

"Wouldn't make you forget your device. People can usually - guess that I exist - if they leave themselves reminders, but they forget again pretty soon after they stop interacting with the reminder."

She makes a record, both for herself and in her auxiliary report. Starts setting a regular reminder. (Neither of these operations involve actions externally visible to eyesight.)

"How soon?"

"Usually in the minutes range, sometimes seconds if someone's base memory is poor."

She calibrates the relevant settings of the reminder accordingly. 

"Can others who don't see you be told of your existence?"

"They'll forget me, too, but... Maybe it's just my world, since you're interacting with me just fine."

"I'd suggest stepping into mine to attempt to disambiguate between that possibility as opposed to this location protecting against it, but exiting to my world is currently prevented. I'm told that shouldn't last overly long.

We don't have the phenomenon in my origin; is it common in yours?"

"People can delete things from existence - the process is really complicated though, so most don't - and deleting things makes you progressively harder to remember. I've used the deletion magic a lot, way more than normal."

"Is it known what causes that?" She's been attempting to read about some various worlds and their apparent assorted phenomena and what their inhabitants know about them. (A few, which is a very, very small fraction, it seems. Not exactly an ideal method for an overview. But if materials exist with more overview and less localizedness, they don't seem to currently be offered here.)

"Resonance, probably, since when you delete something you make the world like it never existed - so people have trouble remembering you ever existed."

...That would be different - and rather more powerful - than deletion (which is quite considerably powerful itself). "It changes events retroactively?" and, "Can the resonance and its source be detected by something other than its effects, or is it construed from them?"

"Yeah to the first, though big changes that impact a lot of people are super hard. You gotta guess right what the world looks like without it, for one. And deleted things are shuffled into the Forgotten World, so you can find them there."

"The Forgotten World?" and, "What takes place with people who would have died or never existed in the previous version, but would be alive or exist given the deletion?" and, "If you were to delete something, and then another user deleted you, would your deletion be returned?"

"It's a parallel world. I don't know if other worlds have the same thing, but it's pretty hard to access - and important to rituals for deleting things."

"And, yeah, you can change who's alive or who exists with deleting, and that's part of why it's hard to do stuff in the past - you need to account for all the people who would or wouldn't be born if you did something."

"And deleting me would undo my deletions, but the fact I've deleted stuff makes me really hard to delete, because no one can remember what I did with my life or the impacts I've had, so you can't describe the world without me accurately enough."

"What is it like as a world? Is living there different from living in your general world? Do those people sent their retain previous memories?

Would deleting things be a protection from being deleted, then?"

She rubs at her forehead. "One question at a time, maybe."

"Ah, apologies." She looks to one of the other tables. "Would you like to sit down? The bar provides one free drink."

"Sure. Sounds good to me."

She moves to sit down at a table within viewing distance of her previous one, and waits to see if the entrant will go to the bar or sit also. 

Heads to the bar, gets something, then heads over to her table to sprawl across from her.