“Posting links should be low-friction, and so it should be fine to post links without comment”—I would like to encourage you to examine this assumption. It depends heavily on the exact context. When few people have links to post, link posting should be low friction in order to encourage more posts. When there are more people posting links, having link posting be low friction is of much less value as quality becomes more important than quantity—indeed quantity can interfere with quality by reducing the chance that these links are seen.
“Posting links should be low-friction, and so it should be fine to post links without comment”—I would like to encourage you to examine this assumption. It depends heavily on the exact context. When few people have links to post, link posting should be low friction in order to encourage more posts. When there are more people posting links, having link posting be low friction is of much less value as quality becomes more important than quantity—indeed quantity can interfere with quality by reducing the chance that these links are seen.