The stories of Secret Subreddit all feature around one location: The Facility. Once an underground laboratory for pseudoscience and unusual research, a long period of silence from the rarely seen executives has lead to it becoming more like a self-sufficient city, complete with a population of outcasts and misfits who've found their way there, one way or another.
While research does still go on, it now has to share space with a sizeable civilian population, all trying to live their lives through the general anarchy and bizarre day to day happenings of the Facility. This cast of characters is diverse, with everything from sorcerers to cyborgs having lived in the Facility at some point.
Another fairly recent change is that after an incident involving one of the Facility's many disposable Interns spilling coffee on a control panel, the main section of the complex was launched into orbit, and after a separate incident involving coffee, it was rocketed through space to an uninhabited planet, deep in barely charted space.
New characters are likely to stumble onto the Facility without being quite sure how they got there (Which is a surprisingly common tale when the staff swap stories on how they arrived there), or to be hired by the executives (Or rather, their lackeys) to fill a niche in the staff roster. Other than that, there's always the potential for people to seek out the place for themselves.