[rob]

I've witnessed bots here on accounts that are years old with no history that start posting multiple times in a short timeframe suddenly after being dormant forever. Makes you wonder how they're getting these old accounts. It's not just new ones.

[dragontamer]

Black market accounts. Some human made them years ago for a price, they are sat on by some black market / grey market guy and now he's selling the accounts for a profit.

Old accounts from multiple social media platforms has a $$$$$ value.

[mrguyorama]

Account takeover is a thing that happens. I doubt HN has the best measures against credential stuffing.