That's my problem with HN as an information source as well. Just an 80-character headline isn't much space to convey information, unless it's extremely simple information. A headline plus a short blurb, like on Metafilter or Slashdot, at least gives a slightly more coherent explanation of what this article is about and why the submitter thought it was interesting, and mitigates the tendency towards only promoting stuff that can catch people's eye in 80 characters.

On HN you can sometimes get that by clicking through to the comments first, but it's kind of a frustrating way to browse links. Some subreddits on reddit have moved back to the Slashdot style by only allowing "text" submissions rather than "link" submissions; unlike HN's text submissions those can also contain clickable links, so the effect is to require people to write a little along with the link, instead of just submitting a link.