Backlink

Backlinks are links from other websites pointing to yours. Google treats each one as a vote — if a reputable site links to you, some of that reputation flows through.

Despite a decade of predictions that "backlinks are dead," they remain the strongest ranking signal Google uses for competitive queries. A site with 500 quality backlinks will outrank a site with 5 in almost every niche, even if the content is similar quality.

Counts:
• Editorial mentions in news articles
• Links from industry-trusted sites in your niche
• Links from government (.gov) or education (.edu) sites
• Real guest posts on reputable blogs

Mostly ignored:
• Directory links (mass submissions)
• Comment spam
• Forum signature links
• Paid links (also risky — against Google's guidelines)
• Press release distribution services

Google's algorithm can distinguish a carefully earned link from one bought for $5 on Fiverr.

1. Guest posts. Pitch a relevant article to blogs in your niche. You write free content, they publish it, you get a byline link back to your site. Skip anyone who charges.

2. Digital PR. Publish original data, a report, or a survey. Pitch it to journalists. Being cited as a source earns editorial links.

3. Free tools. Build something useful and free. If it's good enough, people link to it from their own articles naturally. Ahrefs, HubSpot, and Moz have built their entire SEO on this.