I have recently taken on a client that has been manually penalised for spammy link building by two previous SEOs. Having just read this excellent discussion, http://www.seomoz.org/blog/lifting-a-manual-penalty-given-by-google-personal-experience I am weighing up the odds of whether it's better to cut losses and recommend moving domains. I had thought under these circumstances it was important not to 301 the old domain to the new domain but the author (Lewis Sellers) comments on 3/4/13 that he is aware of forwards having been implemented without transferring the penalty to the new domain. http://www.seomoz.org/blog/lifting-a-manual-penalty-given-by-google-personal-experience#jtc216689 Is it safe to 301? What's the latest thinking?