Planet Earth, A.D. 2050 (Gregorian)
We're preserving human information by writing it on the Moon.
Lasers etch binary code upon the near-side surface.
Nobody likes everything that's been written, of course, and some just can't be satisfied.
And, of course, the density of information recordable upon dust and stone by even the finest laser is magnitudes less than that upon a purpose-made, terrestrial medium at microscopic range but the surface of the Moon is immense.
And the Moon is a lot more stable.
Compared with Earth washing, flowing, shifting, turbulent, cracking, shaking, dissolving, melting and solidifying Earth... compared with Earth, our Moon is placid.
Stately, that's true; beautiful yes... but most importantly for the purposes of an Earth library project, our moon is profoundly stable. This is especially true of the side facing Earth, shielded from Earth-bound rubble.
On the side facing the Earth, not much changes in a million years.
Except when we change it.
The Moon, almost eternally stable, and one side always turned our way, turns out to be a great place to store Earth information.