Google has argued that the most effective way to fight illegal downloads is not to block websites but to "follow the money."
The search giant pointed to a Google-commissioned study from BAE Systems Detica, which analysed websites that rights holders have cited as major havens for pirated content.
In looking at things like number of unique visitors, IP addresses, sources of funding, and preferred formats, "the results suggest that the most effective weapon to tackle piracy is to follow the money - to squeeze the pirates' financing," Theo Bertram, Google's UK policy manager, said in a blog post.
The report found that sites selling unlicensed music are on the decline, while sites streaming free, live TV are seeing the most uptake. This, BAE concluded suggests "that the ease of buying legal copyrighted music is having an impact on piracy."
As a result, Google warned against blocking or filtering websites, a move "that might damage fundamental freedoms." Instead, ad networks, payment processors, and rights holders should join forces and "crack down and squeeze the financing behind online infringement."
The report said that two-thirds of the websites accused of hosting pirated content "display well-known credit card logos," while about 86 per cent of ads on pirate sites come from networks that have not signed on with self-regulatory bodies or committed to strong codes of conduct.
If those credit card companies did not process transactions from these sites and those ad networks also turned away, "the pirate's oxygen supply" - aka money - would be blocked.
Last year, when US lawmakers were discussing the controversial Stop Online Piracy Act (SOPA), Google made a similar argument before House lawmakers. Google copyright policy counsel Katherine Oyama argued that going after the money would be more effective than bills like SOPA and might avoid "the collateral damage to Internet architecture."
Google has come under fire in recent years for facilitating piracy via its search engine and YouTube. Google released an updated copyright plan in Dec 2010, and said last year that it was making "considerable progress" on those goals. In May, the search giant announced plans to disclose the number of copyright-related takedown requests it receives on a daily basis.