SKY Labs Experiment Format
This is a real-world SEO experiment conducted across the SKY network with measurable results over 6 months.
Objective
To test the long-standing SEO debate: Do subdomains perform worse than subdirectories for organic traffic, specifically:
- Measure actual Google ranking treatment of subdomains vs theoretical best practices
- Track crawl budget distribution across multiple subdomains
- Monitor domain authority flow from main domain to subdomains
- Compare indexing speed and depth between different structures
Hypothesis: Modern Google treats subdomains as separate entities, potentially diluting domain authority compared to subdirectories.
⚙️ Setup
Test Structure
18 subdomains under trainwithsky.com
Test Duration
6 months (Aug 2024 - Feb 2025)
Data Source
Google Search Console + Google Analytics
Content Type
Identical structure across all subdomains
Tested Subdomains:
Control Group:
- Main domains: skytts.com, skyconvertertools.com (subdirectory structure)
- Primary subdomain: trainwithsky.com (parent of all test subdomains)
- Content similarity: All subdomains had comparable content depth and structure
📊 Data Observations (Real Numbers)
Organic Traffic Distribution (6-month average)
What Actually Happened
Subdomains indexed independently: Google treated each subdomain as a separate entity with its own crawl budget.
- Crawl distribution: 65% of crawls went to main domain, 35% distributed across subdomains
- Indexing speed: Subdomains indexed 40% slower than main domain content
- Authority flow: Limited authority transfer observed from main domain to subdomains
- Keyword cannibalization: Multiple subdomains competed for same keywords
Negative Findings
- Diluted link equity: Backlinks to subdomains didn't benefit main domain
- Duplicate content issues: Similar content across subdomains caused thin content flags
- Slower rankings: Subdomains took 3-4 months longer to rank vs main domain content
- Crawl budget waste: Googlebot spent significant time crawling duplicate structures
What Didn't Work
Mass subdomain creation without strategic purpose significantly diluted SEO performance and slowed growth.
Specific issues observed:
- Authority fragmentation: Instead of building one strong domain, we built 18 weak ones
- Management overhead: 18 separate Google Search Console properties to monitor
- Content duplication: Similar templates across subdomains created quality issues
- User confusion: Different subdomains for related content confused returning visitors
Key Learning
Subdomains should be used strategically for truly separate businesses, not for content organization. For topical content clusters, subdirectories perform significantly better.
Data-backed insights:
- Subdirectories build cumulative domain authority
- Subdomains require separate SEO efforts for each
- Modern Google still treats subdomains as separate sites
- The "subdomains are treated as separate sites" guidance is still valid
Action Taken
Based on 6 months of data:
- Consolidated 6 subdomains into trainwithsky.com/subdirectory/ structure
- Redirected low-performing subdomains to main domain sections
- Kept only strategically distinct subdomains (learnai, devops, jobs)
- Implemented proper interlinking between remaining subdomains and main domain
- Created a subdomain strategy document for future SKY projects
Result after 2 months of consolidation: Overall organic traffic increased by 28% despite having fewer "domains" in Google's index.
✅ Conclusion
This experiment provided data-driven evidence about subdomain SEO impact:
Validated Theory
Traditional SEO advice about subdomains is still correct. They are treated as separate entities with limited authority transfer.
Practical Insight
Use subdomains only when: The content/service is truly distinct from your main business. For content organization, use subdirectories.
Warning
Creating multiple subdomains without clear strategic purpose will fragment your SEO efforts and slow growth.
Data Transparency: All traffic numbers are from Google Analytics (Aug 2024 - Feb 2025). This experiment cost us approximately 4-6 months of SEO progress that could have been avoided with proper structure from the start.