This is effective advertisement, not a donation. A real ad (with a campaign) would probably have cost much more, and wouldn't continue to be propagated for free months after the ad campaign is over, like this peace of news.
This type of ad is also much harder to filter/block, since not only it appears to be site-native, but also topic-native.
Because it's an overhyped joke successfully utilized by crypto scammers.
Neither content addressing, nor distributed hash tables (or key-value stores, or whatever) were novel ideas.
The combination of the two is not a novel idea.
For p2p, torrents, work as another user already pointed out (initial realease 2001).
For a distributed filesystem, look at Tahoe-LAFS (initial release 2007).
For a full anonymous p2p distributed filesystem, check out (real) Freenet, called Hyphanet now (initial release 2000).
And no, if you need anonymity, an anonymous transport (e.g. using libp2p) is not enough. You need to consider anonymity at each step like Freenet does.
These are three real non-overhyped products one can draw inspiration from. IPFS? not so much.
You can look around for more examples. I always found this Wikipedia page about file sharing in Japan interesting, since it mentions networks not well known to the rest of the world: https://en.wikipedia.org/wiki/File_sharing_in_Japan