SEO What Are Backlinks

A backlink is a link from one website that points to another website. When a website links to yours, it gives you a backlink. Backlinks are one of the most important ranking factors in SEO. Google treats them as votes of confidence — each backlink signals that another website found your content valuable enough to recommend to its own readers.

The Voting System Analogy

Imagine an election. Each vote cast for a candidate counts as support. In SEO, each backlink is a vote for your website. However, not all votes are equal. A vote from the President carries more weight than a vote from an anonymous citizen. In the same way, a backlink from BBC.com carries far more authority than a backlink from a random personal blog with no readers.

How Backlinks Work: PageRank

Google's original algorithm — PageRank — calculated a page's importance based on how many other pages linked to it and how authoritative those linking pages were. PageRank still exists at Google's core, though it has evolved significantly. The basic principle remains: more quality backlinks = more authority = higher rankings.

Diagram: PageRank Flow Through Backlinks

High-Authority Sites:
  [Forbes.com] -----------> YOUR PAGE (Authority received: HIGH)
  [Reuters.com] ----------> YOUR PAGE (Authority received: HIGH)

Low-Authority Sites:
  [newblog2024.blogspot.com] --> YOUR PAGE (Authority received: LOW)
  [spamsite.xyz] -----------> YOUR PAGE (Authority received: NEGATIVE)

Net result: 2 high-authority links beat 50 low-authority links.

Dofollow vs Nofollow Links

Not all backlinks pass authority equally. The link's HTML code determines whether it passes ranking authority.

Dofollow Links

Dofollow is the default state of any link. Google follows these links and passes authority (link equity) from the linking page to your page. These are the most valuable backlinks for SEO.

Nofollow Links

A nofollow link contains the attribute rel="nofollow" in its HTML code. It tells Google not to follow the link or pass authority. Wikipedia, most news comment sections, and many forums use nofollow on all outgoing links.

Diagram: Dofollow vs Nofollow

Dofollow link (standard):
<a href="yoursite.com">Visit this guide</a>
--> Google follows. Authority PASSES. Ranking benefit: YES.

Nofollow link:
<a href="yoursite.com" rel="nofollow">Visit this guide</a>
--> Google may NOT follow. Authority does NOT pass. 
    Ranking benefit: Minimal/None.

What Makes a Backlink Valuable

Not all backlinks help equally. A valuable backlink has these qualities:

From a high-authority domain: Sites with strong domain authority pass more value.
Relevant to your topic: A backlink from a cooking website to your food blog is more valuable than one from a car parts website.
From a page with traffic: Links from pages that actually get visitors send you referral traffic in addition to authority.
In the body of the content: Links placed in the main text carry more weight than links in footers or sidebars.
With descriptive anchor text: Anchor text that describes your page's topic reinforces your keyword relevance.
Dofollow: As explained above, dofollow links pass authority.

What Makes a Backlink Harmful

Some backlinks can damage your rankings rather than improve them. These include:

Links from spam websites or link farms (sites that exist only to sell links).
Links from irrelevant, unrelated websites in bulk.
Links created by automated software (link building bots).
Paid links that are not marked as sponsored (violates Google's guidelines).

Google can manually penalize websites that practice manipulative link building, dropping their rankings significantly or removing them from search results entirely.

How to Check Your Backlinks

Google Search Console: Shows your backlinks under Links → External Links. Free and official.
Ahrefs: The most comprehensive backlink database. Shows all backlinks, their authority, anchor text, and whether they are dofollow or nofollow.
Semrush Backlink Analytics: Similar to Ahrefs with additional competitor comparison features.
Moz Link Explorer: Shows Domain Authority and backlink details.

Key Takeaway

Backlinks are votes of confidence from other websites. Quality matters far more than quantity — one link from a trusted, relevant, high-authority website beats hundreds of low-quality links. Focus on earning dofollow links from reputable, topically relevant sources. Avoid buying links or using automated link building tools, which risk Google penalties.

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