Re: 12-word seed vs 24-word seed? This seems pretty interesting
So you're saying if I post my 12 seed words online, someone can steal my Bitcoins? What's next, if I post the details for my bank but scramble my PIN, someone can steal my euros too? 
That's true indeed! It's unsafe to post the 12 seeds words online because if someone is keeping eye on you then that malicious person might be able to crack your wallet with those seeds by conducting a
brute-force attack to steal the Bitcoins out of it. If I'm not wrong then someone's seed phrase is key to the wallet and brute-force attacks can easily own the perfect combination of the seed phrase if those seeds are posted online.