To expand upon that... The problem with md5 and sha and such is that they are fast. bcrypt is useful because it takes a fixed amount of complexity which can be

To expand upon that... The problem with md5 and sha and such is that they are fast. bcrypt is useful because it takes a fixed amount of complexity which can be specified by the programmer (and later increased). It also uses salts to thwart rainbow tables. The complexity bit is important, though, because as computers get better, you can make it harder to reverse your passwords. Also, the biggest reason any of this is a problem is because password reuse is rampant. You are being entrusted with the password to your user's life - their email, their bank account, their facebook account... treat it with respect.