Sites like Cyberfile.me use these alphanumeric strings to manage user uploads.
These strings are frequently used as "source" links in community forums where users share specific video clips or roleplay scenes. 0h4s4w2hs3j1ijjhen79h_source.mp4
Music and media tracking sites (like Last.fm) sometimes scrape these filenames when users play them through certain media players. Sites like Cyberfile