Krebs follows up on this question, and Ptacek does clarify what he meant:

> BK: Okay. So if the weakness isn’t with the strength of the cryptographic algorithm, and not with the lack of salt added to the hashed passwords, what’s the answer?

>Ptacek: In LinkedIn’s case, and with many other sites, the problem is they’re using the wrong kind of algorithm. They use a cryptographic hash, when they need to use a password hash.

In the next couple of paragraphs, he also elaborates on the reasons for it. The long and the short of it is that SHA1, with or without salt, is far too fast to be used as a password hash. It is so fast, that when computed using a GPU or something similar, you can brute force 10s of thousands of hashes per second. As is elaborated on later in the interview, LinkedIn should have been using [bcrypt][1], which is an adaptive hash that would have slowed the brute force time down to the order of 10s of hashes per second.


  [1]: http://security.stackexchange.com/questions/5605/which-password-hashing-method-should-i-use