Digg is a social-bookmarking site and RSS reader. It highlights the best content on the web as chosen by the Digg community. Bloggers can submit their posts to Digg and use it find interesting content to share.
Delicious is a website that lets you to save your bookmarks in one place, accessible from any computer. Bloggers use it to discover new blogs using the search function and receive traffic from users who discover theirs.
Pinterest is an image website where you can collect and arrange pictures you love. Not only can bloggers use it as a bookmarking tool of sorts, but they can submit images from their blogs to help generate traffic.
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