Website directories are lists of links to websites which are sorted into categories. Website owners can submit their site to many of these directories. Some directories accept payment for listing in their directory while others are free
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Social bookmarking is a way of saving and categorizing web pages in a public location on the web. Because bookmarks have anchor text and are shared and stored publicly, they are scanned by search engine crawlers and have search engine optimization value.
Image linking is a way of submitting images, such as infographics, to image directories and linking them back to a specific URL.