Facebook-specific threads on this from last year:
https://news.ycombinator.com/item?id=24337269 - "An Update About Changes to Facebook’s Services in Australia", 2020-09-01, 158 comments
https://news.ycombinator.com/item?id=24347676 - "Facebook to block news on Australian sites after new law, riling lawmakers", 2020-09-01, 78 comments
The big threads about this issue include:
https://news.ycombinator.com/item?id=26111783 - "Australia to introduce Google, Facebook legislation to parliament next week", 2021-02-12, 269 comments
https://news.ycombinator.com/item?id=26030135 - "Google News Showcase Launches in Australia", 2021-02-04, 54 comments
https://news.ycombinator.com/item?id=25999799 - "Australia’s PM suggests Bing adequate if Google blocks searches", 2021-02-02, 175 comments
https://news.ycombinator.com/item?id=25987671 - "Communications Minister touts the opportunities of a Google-less Australia", 2021-02-01, 49 comments
https://news.ycombinator.com/item?id=25903511 - "Australia’s Proposed “Fox News Tax”", 2021-01-25, 29 comments
https://news.ycombinator.com/item?id=25873001 - "Could Google Really Leave Australia?", 2021-01-22, 51 comments
https://news.ycombinator.com/item?id=25870571 - "The spat between Google and Australia, as reported on HN", 2021-01-22, 95 comments
https://news.ycombinator.com/item?id=25867547 - "Google Threatens to Remove Search in Australia as Spat Escalates", 2021-01-22, 33 comments
https://news.ycombinator.com/item?id=25867264 - "Google threatens to withdraw search engine from Australia", 2021-01-22, 135 comments
https://news.ycombinator.com/item?id=25866493 - "Google threatens to disable search in Australia if media code becomes law", 2021-01-22, 18 comments
https://news.ycombinator.com/item?id=25789773 - "Google looks at pulling all or part of its search engine from Australia", 2021-01-15, 71 comments
Others?