Add a social norm where commenters make short summaries, or quote a couple sentences of new info, without the fluff.

Posting links should be low-friction, and so it should be fine to post links without comment. That said, writing summaries in comments is very useful, and you should feel willing to do that even on links you didn't post.

Maybe we should have subreddits on LW. I'm not sure about this one. Tags serve some of the same purposes, so perhaps what would be ideal would be to subscribe and unsubscribe from tags you're interested in. However, just copying the Reddit code for subreddits would be simpler. It would divide up the community though, so probably not desirable while we're still small.

Different subreddits seem best when used to separate norms / rules of discussion rather than topics. (Topics are often overlapping, and thus best dealt with using tags.) I think something like 'cold' and 'warm' subreddits, where the first has a more academic style and the second has a more friendly / improvisational style, might be sensible, but this remains to be seen.