As it turns out, the idea of filtering the Internet is hardly a new one. In the mid 90s, the CSIRO was asked to investigate the feasibility of filtering Australia’s Internet traffic. The final report is available for reading here.
You may be surprised (or not) to learn that the original report found that mandatory filtering was not a viable option (yes, I’m paraphrasing) but I welcome you to read the report yourself. The content covers a lot of very familiar ground – in particular, packet filtering and “clean feeds”. Each section lists a number of technical and non-technical reasons why mandatory filtering is impractical.
Worth a look.