That's after it's huge. Uber 0.1 was probably just WhatsApp to a couple of drivers.
There are any # of co's not lame early on: Google, Adobe, Zee Aero, Joby, Viv/Siri, Cruise, Magic Leap, DeepMind, Vicarious…
Indexing and rating web pages based on links back to pages. Basically a massive "outer join" on the web. Basically a software implementation of how academic papers are rated, but technically a massive data processing exercise - not just a good idea in theory but required a great deal of engineering skill to implement.