As an AI algorithm engineer, being cited by Jakob Uszkoreit is indeed impressive, but being able to cite "Attention Is All You Need" in a paper is also quite gratifying
What are External Links (Outbound Links)?
External Links, also called Outbound Links/Outgoing Links, are clickable hyperlinks in web pages that point to other independent domains (it's unclear whether pointing to other subdomains counts, as Google also considers them as other websites). In essence, they guide users from the current website to third-party sites through anchor text or URL paths. For example, when an article about "AI development trends" includes a link to the paper "Attention Is All You Need", this link is an external link. Conversely, each of your outbound links is a "backlink" for the target website.
External links are fundamental tools for establishing connections between websites and the internet ecosystem. By actively linking to external resources, they signal to search engines the topical relevance and informational completeness of page content (you can't fit all information into a single page). When a website frequently links to authoritative academic platforms, search engines can more accurately determine your professional domain (i.e., Topic Authority). Additionally, external links provide extended reading and better user experience, allowing users to quickly access more materials, original data, or cross-platform perspectives, thus building a more comprehensive knowledge network. However, the value of external links depends on the authority and relevance of target sites. Blindly linking to low-quality websites (often in link exchange scenarios) may have negative effects.
Core Differences: External Links, Internal Links, and Inbound Links
Reference: Semrush article
In SEO, link building strategies rely on three fundamental link types: External Links (Outbound Links), Internal Links, and Inbound Links (Backlinks):
- External Links (Outbound Links): Hyperlinks pointing to other independent domains. Their core function is to establish connections between the current website and external resources. The value of these links lies in providing extended information to users while signaling content credibility (EEAT) and professionalism to search engines.
- Internal Links: Navigation channels between pages within the same website. Their core role is to optimize site navigation, help users efficiently access related content, and improve search engine crawling efficiency for important pages through weight distribution. Common applications include recommended reading at the bottom of articles, navigation menu directory trees, and keyword anchor text jumps within content. For internal link details, read:
Internal Links: The Most Underestimated SEO Optimization Direction
Internal links are crucial in SEO and user experience. By optimizing weight transfer and user navigation, they help improve page exposure and dwell time. Effective internal link strategies include adding internal links, optimizing anchor text, category tags, and strengthening page relationships through bidirectional links to improve overall site structure and content discoverability.
Read Complete Guide β- Inbound Links (Backlinks): External links from other websites pointing to your domain, also called "backlinks/reverse links". These links represent third-party recognition of content value and directly affect a website's authority score in search engines, making them a core metric in SEO ranking algorithms.
| Link Type | Advantages/Effects | Risks/Considerations |
|---|---|---|
| External Links | β’ Actively recommend external resources, may trigger reciprocal attention (opportunity to gain inbound links) β’ Link to authoritative sites to enhance content credibility | β’ Beware of excessive outbound links causing user loss β’ Recommended resources must follow "relevance + authority" principle |
| Inbound Links | β’ Act as external "votes" to enhance website authority β’ Reflect content quality and industry recognition | β’ Should be acquired naturally through original research and industry cooperation β’ Beware of low-quality or manipulative links causing search engine penalties |
| Internal Links | β’ Connect site resources to form content cluster competitiveness β’ Distribute page weight and improve long-tail content exposure | β’ Need scientific planning of link density and hierarchical structure β’ Inefficient internal links may cause indexing delays or keyword competition internal consumption |
Do External Links Help SEO?
From Google's algorithm logic, external links themselves are not direct ranking signals, but they indirectly affect SEO performance through the following mechanisms:
- User Behavior Optimization: Authoritative external links can reduce bounce rate and extend page dwell time. These user interaction metrics are captured by search engines and incorporated into quality assessment systems.
- Topic Relevance Enhancement: Frequently linking to high-quality resources in specific fields helps search engines establish strong associations between pages and industries, improving long-tail keyword matching accuracy.
- E-A-T Trust Endorsement: In YMYL (Your Money Your Life) fields such as education and healthcare, external links pointing to authoritative sources like government agencies and academic platforms directly strengthen content professionalism, meeting Google's E-A-T assessment framework requirements.
- Not a Requirement: Lack of external links won't cause SEO penalties, but proper use can create incremental value.
- Risk Threshold: When external links exceed 35% of total page links, it may trigger search engine alerts for "excessive traffic diversion" (data source: Search Engine Journal 2023 internal link ratio study).
- Quality Weight: Links to sites with DA (Domain Authority) β₯50 have 3-5 times more SEO benefit than links to ordinary blogs (based on Ahrefs 2024 weight transfer model calculations).
Google officially stated that the SEO value of external links comes from their "enhancement effect" on content quality, not from the linking behavior itself. Reasonable citations in quality content can make external links play a positive role. A research article I read long ago also confirmed that external links are SEO-friendly because: spam pages rarely have outbound links. If you link to reliable resources, you can prove to Google that your page is not spam. When outbound links are exchange links and the website quality is poor, you may receive manual penalties due to too many outbound links.
August 2023 Google semi-official spokesperson Mueller's reply on Reddit, though I don't fully believe it either
SEO Best Practices for External Links
1. Link Motivation: Non-SEO Driven
The core value of external links should serve content completeness, not manipulate SEO (though most are still for link exchange purposes). Compliant motivations include:
- Academic Citations: When citing authoritative journal data to support viewpoints, precisely annotate source paragraph positions and publication times.
- Functional Extensions: When content involves professional tool operations (such as Google Analytics setup), linking to official tutorials can reduce user learning costs.
2. Target Site Quality Assessment
When selecting external link targets, consider the target website's authority-relevance-commerciality (this is a scale, as new websites/new content inherently have lower authority):
- Authority Screening: Use Moz Domain Authority (DA) or Ahrefs Domain Rating (DR) tools, prioritize linking to sites with scores β₯60.
- Topic Relevance Verification: Use Semrush's "Topic Research" feature to analyze whether target pages are in the same semantic cluster as current content.
- Competitor Avoidance: Use SimilarWeb to identify whether target sites overlap with your traffic, avoiding traffic diversion to competitors.
Semrush AS is 64 points
Moz DA is 46 points
Ahrefs DR is 68 points
3. Fine-tuned External Link Management
- For controversial content citations (such as legal litigation reports) or untrusted content, use
rel=nofollowto prevent crawlers from crawling links and transferring weight. - For commercial partnership links, uniformly add
rel=sponsoredattribute, generally for paid or affiliate sponsored content, a type of nofollow. - For external links in user comment sections and other UGC content, force enable
rel=ugc, user-generated content represents links added in blog comments and forum posts, a type of nofollow. - Follow and nofollow tags don't affect user experience, only SEO-related. In September 2019, Google added these two attribute tags. It's recommended to use rel="sponsored" for paid links and affiliate links, and rel="ugc" for user-generated content. Tags are not mandatory, you don't need to manually modify everything, these two attributes are consistent with regular nofollow tags.
Old friend AITDK, you can see I basically default external links to Nofollow
4. Better User Interaction Design
- Avoid generic descriptions: optimize "click here to view data" to "large model training dataset".
- Optimize context: add explanatory statements before links, such as "According to OpenAI's official documentation".
- Use different colors + underline combinations to identify external links.
- Mobile adaptation: retain at least 8px click hotspot around external links to avoid accidental touches.
Whether external links or internal links, they generally change color, and I'll bold particularly important ones
5. Avoid Traffic Overflow/User Confusion
- New Tab Opening Mechanism: Add
target="_blank"attribute in HTML code to ensure users don't leave the site when jumping, open in new tab instead of redirect!!! Otherwise it affects bounce rate, users don't need to press the "back" button to return. For same-domain page jumps (internal links), use same-tab navigation instead of new tab opening, otherwise it causes user confusion.
<a href={addUtmToExternalLink("https://example.com")} target="_blank" rel={getExternalLinkRel("https://example.com")}>Example Link</a>- Traffic Overflow Interception: Set up external link click event tracking through Google Tag Manager to analyze high-frequency loss paths. For external link pages with click rates >15%, consider internalizing related content or establishing partner content alliances.
6. Automated Risk Monitoring System
- Link Health: Set up weekly automatic scans through Ahrefs Site Audit to monitor the proportion of broken external links. Mainly detect target websites and Broken Links/404 pages.
- Weight Leak Detection: Use Majestic's Flow Metrics to identify irregular weight output paths.
- Establish Approval Matrix: Three-level review process from content team β SEO specialist β legal advisor (small websites don't need to be so exaggerated).
- Historical Content Review: For articles published more than 2 years ago, check the status of external link target sites quarterly (can use Wayback Machine archive verification).
Check all target websites of your external links
Ahrefs external link check
The following content about link exchange was previously posted on Jike, and since it's most directly related to external links, I moved it here:
Link Exchange
For global AI/SaaS websites, don't randomly add/exchange links, don't appear "εζ ιΎζ₯" (friend links) and corresponding anchor text. Narrowly defined friend links (placed in footer) are like AIGC and KOL, pure Chinese internet concepts (websites with these concepts must be developed by Chinese teams). For Chinese websites, it doesn't matter, webmasters and users are used to it.
But if you're targeting the global market, can you imagine English users seeing "Friend Links" and "Friends" with a confused look? The closest concepts to friend links are:
- Content form: Reciprocal Links, spontaneously generated links between websites pointing to each other.
- Display form: Useful Links
This is PhotoAI's footer. The reason InteriorAI link was added is because both websites belong to independent developer Peter Levels. It's fine to direct traffic to your own or partner websites.
This is Feishu's friend links page, a safer approach. First, they're all ByteDance's own products. Second, a separate aggregation page was created for friend links, with only a link to this aggregation page in the footer.
Risks of Randomly Adding/Exchanging Links
- The other party is an illegal website or the other party's Tiered Link points to illegal websites.
- Many websites link to each other - link farms/Link Farm.
- The other party's website doesn't operate long-term - Broken Links appear.
Don't think Google doesn't know you're using link farms/large-scale link exchanges to boost website weight. Third-party tools like Semrush can clearly see your website's Link Building. This set of practices in China are leftovers from overseas black hat SEO.
The result is either website devaluation or being added to Google's blacklist or entire domain penalty. Not doing external links just means poor SEO performance/slow growth, but doing wrong external links can destroy the entire website. It doesn't matter for independent developers' hobby websites, but branded domains shouldn't mess around. Link exchange is fine, but all Outbound Links should only appear in Blog and Customer Stories, and linked websites should be checked separately with different third-party tools (Ahrefs, Semrush, Moz) for Domain Authority and Spam Score.
Conclusion
External links are hyperlinks in website content that point to other external pages. They not only provide users with authoritative information sources for extended reading but also signal content credibility to search engines by linking to high-quality sites. From an SEO perspective, proper use of external links helps establish topic relevance and improves search engines' assessment of page professionalism. Additionally, citing industry authoritative materials can enhance user trust and reduce bounce rate. However, be careful: excessive stacking of irrelevant links or directing to low-quality websites can harm SEO performance. It's recommended to follow the "relevance + authority" principle and appropriately use nofollow attributes to control weight transfer, achieving a balance between user experience and search engine optimization.