I agree with what others have posted already, add a "rounds" parameter to the site. Asking the site owner to do this is much more productive than trying to burn him at the stake...

People can use their birth year as the rounds number and they will easily remember it. The rainbow table computers will have to do much more work, if they compute all rounds from 1900 to 2000 they will have to do 196,950 hashes per password instead of 1! (http://www.wolframalpha.com/input/?i=1900%2B...%2B2000)