Speaking as a writer for different communities, there are 2 problems with this:
Duplicate content: unless explicitly canonized via headers, Google is ambiguous about which version should rank for keywords. This hits small & upcoming authors like a ton of bricks, because by default, the LW version is going to get ranked (on basis of authority), and their own content will be marked both as a duplicate, and as spam, and their domain deranked as a result.
“An audience of your own”: if a reasonable reader can reasonably assume, that “all good content will also be cross-posted to LW anyways”, that strongly eliminates the reason why one should have the small blogger in their RSS reader / checking once a day in the first place.
The HN “link aggregator” model works, because by directly linking to a thing, you will bump their ranking; if it ranks up to the main page, it drives an audience there, who can be captured (via RSS, or newsletters); and therefore have limited downside of participation.
Speaking as a writer for different communities, there are 2 problems with this:
Duplicate content: unless explicitly canonized via headers, Google is ambiguous about which version should rank for keywords. This hits small & upcoming authors like a ton of bricks, because by default, the LW version is going to get ranked (on basis of authority), and their own content will be marked both as a duplicate, and as spam, and their domain deranked as a result.
“An audience of your own”: if a reasonable reader can reasonably assume, that “all good content will also be cross-posted to LW anyways”, that strongly eliminates the reason why one should have the small blogger in their RSS reader / checking once a day in the first place.
The HN “link aggregator” model works, because by directly linking to a thing, you will bump their ranking; if it ranks up to the main page, it drives an audience there, who can be captured (via RSS, or newsletters); and therefore have limited downside of participation.