What information does the author give the reader about the EROS system? What role does it play in the story?

The EROS system is a chat forum owned by Jan Krislov. The system has three levels, the third of which is reserved for intense sexual chat. The owner is very concerned about clients' privacy, and all accounts are blind. There is a promise of absolute privacy. The EROS system, and its set up, is important to the story because this is the system the killer uses to track down victims. It shapes the characters, the setting, and the plot of the story.