... and naturally there's a DMCA equivalent in every country in the world for just that reason... oh, wait.
In actual fact, the DMCA attempts to inject some common sense into the 'who to sue' decision - it wouldn't need to exist if some people didn't automatically jump for the money-grab rather than targetting the people that are actually at fault.
Every time an ISP or carrier is forced to blacklist a site, they should blacklist both the site (complying with the law), and the requestor's site too (in the case of the RIAA and the MPAA, they could blacklist both that site, and a randomly chosen member of the association) - 'We decline to transport your data'.
A bit of cooperation between say VISA and Google could have a similar effect for payments too - you block via VISA, Google declines to include your site in its search spider, and therefore its search results. You block via Google, Google declines to include you in its search spider.
I wonder how long this nonsense would last if someone like Sony or Viacom got wiped off the UK or US Internet landscape for a few weeks.