It's interesting that there are great blogs out there known generically as 'link blogs' - that essentially are curated sites that if you like the blogger and their interests - the chances are you will like what they link to.
I was struck by this:
Granted, I’ve been known to paste a few sentences into a post and click publish with little or nothing added, but there’s a big difference between giving readers a taste, thus forcing them to click through to read the whole story, and simply copying and pasting the juiciest bits on your own site. There’s nothing wrong with linking to a great article by way of a short quote, just don’t take advantage. The point is for your readers to share in what you found.
I do that – i always try to add comment – I want people to click through. I want to add value. But where are the ‘rules’ ? Really? How do you judge the value of the comment ? Is it worthy ?