I personally always, always try to link early and often throughout any sourced piece that I write. I’m not perfect, so I do miss links once in a while, but I attempt to correct them whenever possible. It’s only the right thing to do. We have a link section at the bottom over at TNW but I very, very rarely use it. I suppose I should duplicate the source links at the bottom of the post, but I feel that an inline link clearly attributed to the source so that it’s not a mystery is the best way to go.
Not one word, not a bit of punctuation, but either on the name of the site you’re referencing or a portion of the text that is clearly an indication that ‘more information exists here’.
There is only one reason why you wouldn’t link right in the body of your text, as far as I’m concerned: you don’t want people to click on it.
This is why when I link to interesting things I have read, I use an excerpt and link the author’s name or the site on which the article was posted. I also try to use the Link post type on WordPress.com, which changes the post title to be a link out to the original article.
I quote things on my blog not because I’m trying to get eyeballs myself, but because I find what these people have written to be genuinely interesting and I think if you are pointed in their direction, maybe you’ll find another blog or site to add to your reading list.
Coming soon: a discussion on why Fever is the best RSS reader in the universe because it helps you find source articles and new things to read. (Oh, and owning your data FTW.)