I got that. I was only intending to point out a different attack, where the attacker may not know the algorithm or even use their own cpu to do the brute forcing, but let Google do it. I guess it was a leap to go all the way to "roll-your-own". I agree that secret salt makes this less likely, but considering the Google attack may influence implementation including how the salt is selected or maybe whether the resulting hash is ever published in a Google-able space.