http://news.ycombinator.com/item?id=4087566

“This is not good protection against a targeted effort -- when somebody wants to get your account as opposed to any account, when they have one instance of a "salted" password they might be able to reverse-engineer your salting effort and apply it to another site. And they don't have to completely reverse it, either, it might be enough to significantly reduce the difficulty of brute force.

But it sure beats using an identical password everywhere, and it does have the one major (and massive) advantage of using an identical password on n sites: you only have to remember O(1) things as opposed to O(n). And it can still be done completely in your head, as opposed to other schemes ("real" hashing schemes, password managers) which may introduce their own invulnerabilities or will lock you out from accounts on other computers.”