This post made me curious: how many private keys have been posted on Bitcointalk?
To find out, I searched all downloaded posts (which took hours) for anything that could be a Bitcoin private key. That resulted in 9375 potential keys (not all of them are valid, and no, I won't post the list).
Yesterday, I imported the private keys into a new Bitcoin Core wallet (this took only a few minutes), and did a rescan (which took forever, but was mesmerizing to watch: the balance went up and down by many Bitcoins, and this kept going for hours! I left it to finish overnight.
This morning, Bitcoin Core was hanging. I killed it, restarted it, and it took forever to load the wallet (which had grown to 2.2 GB during the rescan). Eventually, it worked! It's up to date, and the total balance is 0 (as expected). Every few minutes, Bitcoin Core is unresponsive for a few minutes, most likely because of the large wallet combined with a lack of processing power. It's not very nice to work with, and consumes 1 full CPU core.

Scrolling through the transactions, it's obvious any incoming transaction instantly gets sweeped, usually at a high fee. I assume many people have systems monitoring all compromised private keys, and they're competing against each other to steal the funds before someone else does. Back in the days, it happened to large amounts of Bitcoins, but the more recent transactions are mostly small. Except for last month (January 24): this address received 0.84362383BTC, which was instantly sweeped. The private key was posted 2 months earlier:
Someone made a very expensive mistake funding it. I'm hoping pbies can tell me where the private key comes from.

TL;DR
Don't post your private keys! Don't post your seed phrases! Don't try to be smart by creating a brain wallet!

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