SKY Labs Experiment Format
This experiment measures Google's crawl and index behavior on brand new subdomains. We launched six subdomains across SKY TTS, SKY ConverterTools, and TrainWithSKY, each with 20 articles, and varied three factors: sitemap submission, internal links from main domain, and social signals (tweets + bookmarks).
Objective
To quantify the impact of three common SEO tactics on indexing velocity for brand‑new subdomains:
- Sitemap submission: Does submitting a sitemap via GSC on day 1 make a difference?
- Internal links: 5 contextual links from the primary domain (skytts.com → new subdomain) vs none.
- Social signals: 10 tweets + 5 social bookmarks (Reddit, Pinterest) vs zero external signals.
Hypothesis: Subdomains with sitemaps and internal links will see first indexed pages within 48h; social signals will accelerate depth of indexing.
Setup
Subdomains
6 new subdomains (2 per platform)
Articles each
20 (total 120 articles)
Tracking
GSC, IndexBlaster, custom logs
Duration
28 days (Feb 2026)
Experimental conditions:
Sitemap only
XML sitemap submitted day 1; no internal links, no social.
Internal links
5 links from primary domain + sitemap.
Results Overview
Indexing velocity: pages indexed over time
What Worked
- Internal links from primary domain: cut first‑index time from 7d → 3d (57% faster).
- Social signals + links: 2.5 days to first page, and 96% of pages indexed within 4 weeks.
- Sitemap alone helped but needed at least one link to perform well.
- Subdomains of established domains (SKY TTS, etc.) benefited from parent authority – even control got indexed faster than a completely fresh domain.
What Didn't Work
Relying solely on sitemaps without any backlink context.
- Sitemap-only subdomains: Took 7 days for first page, only 61% indexed after 28 days.
- Social signals alone (without internal links): In a side test (2 extra subdomains), social without links performed only slightly better than sitemap-only – links matter more.
- Low-quality content: Thin pages (<300 words) indexed slower even with signals.
- Over‑optimized anchor text in internal links didn't change speed, but natural anchors worked just as well.
Key Learning
For new subdomains on established roots, the fastest path to indexing is: internal links from main domain + sitemap + initial social mentions.
- Internal links are non‑negotiable: They cut discovery time by more than half.
- Social signals accelerate depth: They help Google crawl deeper into the subdomain.
- Sitemaps are table stakes: They ensure all pages are known, but without links they don't guarantee crawl.
- First page indexed within 3 days is achievable if you combine at least two signals.
Action Taken
Based on 28‑day experiment:
- All new subdomains (SKY TTS, ConverterTools, TrainWithSKY) now receive 3‑5 contextual internal links from primary domain within 24h of launch.
- Sitemap submission automated via custom script on launch day.
- Social seeding: at least 5 tweets + 3 bookmarks (Reddit/Pinterest) for each new micro‑site.
- Content threshold: minimum 600 words per article to improve indexation depth.
- Monitoring: weekly GSC reports to track indexing velocity.
Result: Subsequent subdomain (launched March 2026) had first page indexed in 2 days, 90% indexed in 3 weeks.
SKY Ecosystem Backlinking
This experiment was conducted across our network. Adjust and explore the platforms:
Each platform contributed subdomains to the test — click to visit and see live examples.
Conclusion
This experiment demonstrates that while new subdomains inherit some authority from their root domain, deliberate signals dramatically accelerate indexing. Internal links from the primary domain are the strongest accelerant, followed by sitemaps and social mentions. The combination yields near‑complete indexation within one month.
Validated
Internal links + sitemap + social signals = 2.5d to first indexed page (vs 12d baseline).
Practical Rule
Launch new subdomains with at least 3 internal links from main domain and submit sitemap immediately. Add social mentions within first week.
Warning
Sitemaps without links lead to slow indexing. Don't rely on submission alone.
Data Transparency: Full dataset available on request. All subdomains were property of SKY ecosystem and tests followed Google's guidelines.
Related Experiment
Indexing Speed Test for New Subdomains
Documenting Google's indexing speed for newly launched subdomains under different conditions: with/without sitemaps, internal links, and social signals.