Backlinks are links from one website to another. They are important for search engine optimization (SEO) because they help search engines like Google determine the credibility and relevance of a website. When a site has many quality backlinks, it is often ranked higher in search results. These links can come from various sources, such as blogs, news articles, or social media. The quality of a backlink matters more than the quantity; links from reputable sites carry more weight. Building a strong backlink profile can improve a website's visibility and attract more visitors.