> Yes, but the internet is not purely communication, it's also a store of knowledge.

Who owns the data?

>Also, even records of mundane communication people had throughout thousands of years in the past is of great value to archaeologists in learning about how people lived their lives and how different events affected them.

Meanwhile, works by Archimedes, Homer and Shakespeare, as well as innumerable other cultural artifacts, have been lost to time. As well as the original tapes of the moon landings. The ancient Sumerians writing their tax records in cuneiform never intended to leave a record for the ages. We still probably wouldn't know how Egyptian hieroglyphics worked if not for one artifact that happened to have it printed alongside known languages - and we still have no clue about Linear A, and many other languages.

What gets left behind as an artifact of the ages tends to be determined by random chance, and beyond that, the cultivating desires of the wealthy. In other words, it almost certainly won't be you or I who decide the value or longevity of our work.

>Since we live in a time where we have the privilege of rediscovering the past in greater detail than ever, we should have the introspection to be mindful of what we are leaving for our future as well.

The web wasn't meant to provide a lasting store of knowledge. It is ephemeral and stateless by design. If you want people to think long term about the collective data archive of humanity, asking everyone to just never delete anything is not going to cut it.