Google and Yahoo have said that they strongly oppose a proposed Australian law that would block all web traffic that would be "refused classification" – the Australian equivalent of "not rated" – if it was a book or a movie.

The Safe Internet Group issued a statement denouncing the censorship efforts on behalf of the search giants, the Australian Library and Information Association, and several other organizations this week, saying that "as a large proportion of child sexual abuse content is not found on public websites, but in chat-rooms or peer-to-peer networks, we know the proposed filtering regime will not effectively protect children from this objectionable material. In fact, the policy may give parents a ‘false sense of security,’ encouraging them to reduce their supervision."

Experts say that search engine optimization (SEO) in Australia could be heavily affected if the censorship law is enacted, since a number of widely-used websites like YouTube could cause severe bottlenecks in the filter, slowing performance to a crawl. Additionally, the filter is highly fallible, as a teenage hacker has already proved, according to tech news website The Register.