I've been considering for a little while this question. Some minor research hasn't lead to a solution but there are lots of silos, just not the one I'm looking for.
Something in the same nature as this video, showcasing/documenting the boot sounds (and logos) of all major Windows releases: https://www.youtube.com/watch?v=ACEkZQyCc4Y
... but specific to major web properties, like Google, its search results and UI layout, possible animation, or Facebook's UI and UX and animation evolution.
one site, http://uxarchive.com only showcases iOS apps. That's great, despite the domain name is way more generic than iOS. I've referred to numerous other iOS UX and style sites like that before.
I have been saving a number of old publicly-released iOS apps, old twitter and facebook, etc, backing them up outside of the iTunes MobileBackups thing, just for my own reference.
But is there any public site, that covers the evolution of major web properties and their products?!