What Are Backlinks? A Plain-English Guide
A backlink is a link from another website to yours. How they work, why Google still cares, and what separates a good link from a useless one.
A backlink is a link on someone else's website that points to yours.
Google treats it like a vote. If a respected site links to your page, it's vouching for you, and enough of those votes from the right places is what moves a page from page 2 to page 1. It's the whole idea behind link building.
The basics haven't changed much in twenty years. What has changed is how good Google got at ignoring the junk.
How a backlink works
Site A writes an article and links to a page on Site B. That link sends visitors, but more importantly it passes some of Site A's authority across to Site B.
In the HTML it's just a normal link:
<a href="https://yoursite.com/page">the anchor text</a>
The clickable words are the anchor text, and they tell Google what your page is about.
Why Google still cares about backlinks
Google was built on links. The original PageRank idea was simple, a page linked to by lots of important pages is probably important itself.
Twenty-odd years later Google uses hundreds of signals, but links are still among them, and they remain one of the hardest to fake. Content is cheap to produce now that AI can write it, so a link from a real site that chose to mention you is worth more than ever.
And AI search runs on the same foundations. AI Overviews and chatbots lean heavily on pages that already rank, and the pages that rank tend to be the ones with links.
The terms you'll see everywhere
| Term | What it means | Example |
|---|---|---|
| Backlink | One link from another site to yours | BBC links to you 5 times = 5 backlinks |
| Referring domain | One unique site linking to you | Those 5 BBC links = 1 referring domain |
| Anchor text | The clickable words in the link | "best running shoes" |
| Internal link | A link between pages on your own site | Your blog post linking to your pricing page |
| Outbound link | A link from your site to someone else's | You citing a study on another site |
Referring domains matter more than raw backlink counts. 100 links from one site is still one vote, 100 links from 100 sites is 100 votes.
Followed vs nofollow links
Every link can carry a rel attribute that tells Google how to treat it. The full breakdown is in dofollow vs nofollow links.
| Link type | What it looks like | When it's used | Passes authority? |
|---|---|---|---|
| Followed | No rel attribute | Normal editorial links | Yes |
| Nofollow | rel="nofollow" |
Links the site doesn't want to vouch for | Usually not, Google treats it as a hint |
| Sponsored | rel="sponsored" |
Ads, paid placements, affiliate links | Usually not |
| UGC | rel="ugc" |
Comments, forums, user content | Usually not |
Google has treated all three as hints rather than hard rules since 2020, so a nofollow link can still count sometimes. Don't chase them for rankings, but don't panic about them either, a natural link profile always has some.
What makes a good backlink
Not all links are equal. One link from a relevant, trusted site can beat fifty from random ones.
| Signal | Good link | Useless link |
|---|---|---|
| Relevance | Site covers your topic | Site covers everything from casinos to CBD |
| Authority | Real site with its own links | Brand new or propped up by spam |
| Traffic | Gets real organic traffic | Ranks for nothing |
| Placement | In the body of an article | Footer, sidebar or a 500-link page |
| Anchor text | Natural, fits the sentence | Exact keyword, crammed in |
| Editorial standard | Site turns down weak content | Publishes anything for anyone |
Traffic is the best single check. If Google sends a site real visitors, Google trusts it, and that trust is what a link borrows.
Bad backlinks and what happens if you get them
The links Google's spam policies call out are the ones built purely to manipulate rankings:
- Private blog networks (PBNs) set up only to sell links
- Link farms and auto-generated directories
- Paid links that pass authority with no
rel="sponsored" - Excessive link swaps ("you link to me, I'll link to you")
- Links hidden in widgets, footers or hacked sites
The good news is that Google mostly ignores spammy links now rather than penalising you for them. Its SpamBrain system was built to neutralise them. If you're worried about what's pointing at your site, run a backlink audit. The bad news is you've paid for something that does nothing, and if you build enough of them deliberately you can still get a manual action.
How to check your backlinks
You don't need to pay to get started.
| Tool | Cost | What you get |
|---|---|---|
| Google Search Console | Free | Top linking sites and pages, straight from Google |
| Ahrefs Webmaster Tools | Free for sites you own | Full backlink list for your verified site |
| Ahrefs free backlink checker | Free | Top 100 backlinks for any site, including competitors |
| Ahrefs, Semrush, Majestic (paid) | From around $50 a month | Full data on any site, history and alerts |
Start with Search Console for your own site, then look at what your top 3 competitors have. That gap is your link building plan, and it's how you work out how many backlinks you actually need. When you're ready to close it, start with how to get backlinks.
The short version
- A backlink is a link from another site to yours, and Google treats it as a vote of trust
- Referring domains (unique sites) matter more than total links
- Relevance and real traffic beat any authority score
- Spammy links mostly get ignored, so they're wasted money rather than a death sentence
- Check your own links in Search Console, then compare against whoever's ranking above you
Links aren't magic. But in most niches they're still the difference between the page that ranks and the page that's "really good content" sitting on page 3.