Link Juice

Link juice is the informal SEO term for the value a link passes from one page to another. When page A links to page B, it sends part of its own authority along, and that transferred value is what the industry calls link juice. The expression is slang and does not appear in Google's own documentation, where the neutral term is link equity, but the mechanism behind it is real.

The principle comes from PageRank, the algorithm Google was built on: links work as recommendations, and pages with many good recommendations rise in the rankings. How much value a single link carries depends on several things:

• The authority of the linking page. A link from an established page weighs more than one from an unknown.
• Relevance. Links between pages on related subjects count for more than links with no thematic connection.
• The number of links on the page. The value is divided among all outgoing links, so one link among five passes more than one among a hundred.
• The link attributes. A nofollow link signals that the sender does not vouch for the target, and passes no value by default.

The mechanism is not reserved for backlinks from outside. Value flows the same way through a site's own internal links, where a strong guide that has collected backlinks over the years passes authority on to the pages it links to. The guide to internal link building deals with steering that distribution on purpose.