they may also be effects of less than perfect implementations of URLs: here on HN every comment has a URL, which is really excellent. There's also a great signa

they may also be effects of less than perfect implementations of URLs: here on HN every comment has a URL, which is really excellent. There's also a great signal-to-noise ratio on each page - I'm not talking about the quality of the content (which is also excellent) but the fact that there's very little distracting supplemental content on each page, thus reinforcing the idea that the URL is pointing to your comment, rather than some undefined ephemeral 'page' on HN. The web at large however, does not fully embrace this level of detail and focus in URLs. So users do not feel comfortable using URLs to link readers to discrete packets of information, they feel safer just copying the data. This is just a theory.