: It counts the milliseconds elapsed since January 1, 1970.

: MP4 files can contain metadata (EXIF data) that reveals the creator's location, device type, and software version. Analysis of Media File Distribution

: Developers use these strings to ensure filenames are unique and prevent files from being overwritten.

Billions of files like 1661736428973.mp4 exist across the internet. Without proper indexing, these files become part of the "deep web"—content that is not necessarily hidden but is invisible to standard search engine queries because it lacks descriptive text.

Websites often rename user uploads to timestamps to maintain a clean database. This removes the "human" context of the file (e.g., "vacation.mp4") and replaces it with a "system" context. 2. The "Dark Web" of Unlabeled Content