I don't know that it's that simple. The point that Australia's defamation laws probably allow for overreach is hard to argue against, but at the same time, I don't think we should give companies free rein. Search engine companies undeniably influence what they present; in some cases, through manual interference. How much would they have to interfere before they could be considered a publisher? Arguably, there should be some system of legal accountability here, but the law is behind the times, as it always is (especially in Australia)