I completely agree with you and everyone else who takes this stance.
However in this case I'm willing to let it slide as in the past two days this story has been submitted three times* with a total of 30 upvotes and one comment between them.
In cases like this I usually upvote the first submission and file under 'Things that I think are interesting, but other people seem not to'.
Fair enough, but the official guideline is as follows:
"Please submit the original source. If a blog post reports on something they found on another site, submit the latter."
I think PG sacrifices a lot of clarity for some cleverness here, so here's my rewrite, that I believe is identical in spirit, and hopefully at least slightly clearer:
"Please submit the original source. If a blog post reports on something they found on another site, submit the site the blogger found it on."
Personally, I'm not a rules nut, but he DID ask for the official stance.
In some instances it is more appropriate to link to a blog:
Don't abuse the text field in the submission form to add commentary to links. The text field is for starting discussions. If you're submitting a link, put it in the url field. If you want to add initial commentary on the link, write a blog post about it and submit that instead.
Personally, I think a comment explaining the motivation for linking to a blog rather than the original source, as dshankar provided, is sufficient to justify a blog link.
Definitely true, but you need to determine if the blog post is adding value to the discussion, or just sensationalizing it. The world is full of people who can borrow a few lines and blow them out of proportion, but we should (and do) expect HNers' to do better than that.
A lot of blog posts wind up being just extremely wordy retweets.
I'd also submit that a blog post is the way to go if the source material is either too technical or too difficult to follow, and a blog post simply makes more sense to the HN readership. Or, even if the article is just way too long. Linking straight to a Nature article may be too much for the casual reader.
