Their donate page says they host 45 PB of data (45k GB). That is a mind boggling amount of data to have available online and can't be cheap. This is absolutely a cause worth donating to.
Oh wow, hadn't seen that one -- that was in the aftermath of the 2011 Thailand floods that seriously impacted hard drive availability, there was almost nothing in the supply channel so we had to shuck external drives.
Sadly there's not really a great one-stop page for this kind of info -- https://archive.org/web/petabox.php exists but is sadly outdated (I'll see about rewriting it sometime). We do public tours on Friday afternoons of the main office/datacenter (and our big annual event is coming up next Wednesday if you happen to be in the Bay Area: https://www.eventbrite.com/e/world-night-market-the-internet... )
Just FYI, if you donate they'll add you to their spam list. I donated a couple years ago and got some garbage in my mailbox, but they they apologised and said it was unintentional, so fair enough - everyone makes mistakes.
But guess what arrived just a couple weeks ago? Yeah, more trash in my mailbox.