SKY Labs Experiment Format
This is a controlled SEO experiment conducted across five SKY ecosystem domains to isolate the impact of internal linking structures on early-stage content discovery.
Objective
To determine the optimal internal linking strategy for low-traffic multi-domain networks, measuring:
- Crawl depth: How many clicks from homepage until a page is discovered by search bots
- Discovery rate: Time between publication and first Google indexation
- Link equity distribution: How PageRank-style value flows through different architectures
- User engagement: Whether internal links increase pageviews and time-on-site
- Crawl budget efficiency: Ratio of crawled vs. indexed pages
Hypothesis: A "hub-and-spoke" model with topic clusters will outperform flat sitewide linking for both crawl depth and user engagement on low-authority domains.
⚙️ Setup
Test Domains
5 SKY sites: 3 strategies, 2 controls
Test Duration
4 months (Nov 2025 - Feb 2026)
Content Base
35-40 pages per domain (fresh + existing)
Tools Used
GSC, Custom Python crawler, Ahrefs
Linking Strategies Tested:
Flat / Sitewide
Approach: Every page links to every other page via sidebar/footer
- + High internal link count
- - Diluted relevance signals
Hub & Spoke (Topic Clusters)
Approach: Pillar pages with cluster content linked bidirectionally
- + Strong topical authority
- + 47% faster indexation
Contextual Only
Approach: Links only within relevant content (no navigation links)
- + High relevance
- - Slower discovery for deep pages
Domains & Control Setup:
SKY TTS
Strategy: Hub & Spoke (topic clusters)
- 5 pillar pages
- 25 cluster articles
SKY ConverterTools
Strategy: Flat sitewide (control)
- All pages linked in footer
- No topic hierarchy
TrainWithSKY
Strategy: Contextual only
- Manual in-content links
- No nav/sidebar links
SKY Dev Blog
Strategy: Hub & Spoke (second test)
- Technical pillars
- Code snippet clusters
SKY Analytics (control)
Strategy: No internal links (baseline)
- Only homepage links
- Orphaned content
📊 Data Observations
Content Discovery Funnel (30-day average)
Pages crawled 89% of total
Pages indexed 76% of total
Pages with traffic 34% of total
Key insight: Hub & spoke domains indexed 92% of pages within 7 days, vs 68% for flat linking.
What Worked
- Topic clusters (hub & spoke): Reduced crawl depth from 4.2 to 2.1 clicks; pages indexed 47% faster
- Bidirectional linking: Pillar pages linking to clusters AND clusters linking back to pillar created authority loops
- Contextual anchors: Descriptive anchor text improved relevance signals (vs "click here")
- Related posts modules: Increased pageviews by 28% on cluster pages
What Didn't Work
- Sitewide footer links: Diluted link equity; Google seemed to ignore most of them after ~20 links
- Over-optimized anchors: Exact-match anchors on 50%+ links triggered "spammy" filters (temporary ranking drop)
- Orphaned content: Pages with 0 internal links took 23+ days to index (if ever)
- Cross-domain linking: No measurable benefit at low traffic levels (wasted effort)
What Didn't Work
Spraying links everywhere (sitewide footers/sidebars) wasted crawl budget and provided no SEO benefit beyond 15-20 links.
Specific failures:
- Automatic reciprocal links: "You may also like" plugins that linked randomly increased bounce rate
- Excessive links on one page: Pages with >100 internal links saw reduced crawl frequency
- Linking to irrelevant pages: Confused both users and search bots (lowered time-on-page)
- Forcing deep links: Pages 5+ clicks from homepage still got indexed, but took 3x longer
Key Learning
For low-traffic multi-domain networks, a hub-and-spoke model with topic clusters outperforms all other linking strategies. It reduces crawl depth, accelerates indexation, and improves user engagement metrics.
- Depth matters: Pages within 2 clicks of homepage indexed 4x faster than depth 4+
- Relevance > quantity: 10 contextual links > 50 sitewide footer links
- Pillar pages are magnets: They accumulate more backlinks naturally and pass equity to clusters
- Internal linking = site architecture: It's not just about links, it's about organizing content
Action Taken
Based on 4 months of data across 5 domains:
- Migrated all SKY sites to hub-and-spoke architecture with 5-8 pillar pages per site
- Implemented "related by topic" modules instead of random related posts
- Capped footer links at 15 most important pages (removed 50+ link footers)
- Created internal linking templates for new content (always link to 2-3 cluster pages + pillar)
- Monthly crawl depth audits using custom Python script + GSC data
Result: 3 months post-implementation, indexation rate increased from 71% to 94%, and organic traffic across the 5 sites grew by 112% (combined).
✅ Conclusion
This experiment confirms that for low-traffic sites, intelligent internal linking (topic clusters) is one of the highest-ROI SEO activities:
Validated
Hub & spoke model reduces crawl depth by 50% and cuts indexation time from weeks to days.
Practical Rule
Every page should be reachable within 2-3 clicks from homepage AND from related topic pages.
Warning
Don't let internal links become spam. Keep them contextual, useful, and limited to ~50 per page max.
Data Transparency: All metrics from Google Search Console, Ahrefs, and server logs. The control domain with no internal links (SKY Analytics) saw 0 organic traffic growth during the experiment. Hub & spoke domains grew traffic an average of 134%.