Sitewide links are hyperlinks that appear on every page of a website — most commonly in the header navigation, footer, or sidebar — so that a single domain contributes dozens or thousands of individual link instances pointing to the same target. Before Google’s Penguin update in 2012, sitewide links from high-authority domains were routinely used as a link-building tactic. Post-Penguin, Google began consolidating sitewide links so that the full network of identical links from one domain is treated more like a single editorial vote rather than hundreds of separate endorsements. Sitewide links from legitimate sites such as a web design credit in a footer are generally harmless, but paid sitewide link schemes — where a site purchases a footer or sidebar placement across a partner network — are a violation of Google’s spam policies and can trigger a manual or algorithmic penalty.