Blockbuster has purchased Movielink, an ailing movie download service cobbled together by film studios to combat online piracy. The deal will give Blockbuster access to movies from Sony, Universal, Paramount, MGM, and Warner Brothers. Netflix’s download service, by contrast, offers a limited selection of mostly older movies. The deal is the latest salvo fired in the consumer-friendly war of the movie rental services. No word yet on how long hackers might take to crack the new download service.