All major internet sites, anybody with more than 50.000 passwords, should design or configure a unique algorithm (consisting of course of standard one-way hash functions like SHA2 etc) for their site, in order to make development of highly optimized password brute-force technologies a “per-site” exercise for attackers.

Poul-Henning Kamp – http://phk.freebsd.dk/sagas/md5crypt_eol.html