Answer engines
How the answer engines themselves behave: what each surface shows, how often, and how a source ends up named in an answer.
- 25 published entries
- A9 grade A
- B3 grade B
- C13 grade C
- earliest re-check due 2027-03
A grade describes where an entry's sources come from, not how likely a change is to work. How grades are used
- Aofficial documentation or a standardR-056
ChatGPT search and fetchers
Re-check due 2027-06 - Aofficial documentation or a standardR-058
Copilot uses Bing index
Re-check due 2027-03 - Aofficial documentation or a standardR-090
Crawler access
Re-check due 2027-03 - Aofficial documentation or a standardR-098
Google AI search does not require special AI markup
Re-check due 2027-06 - Aofficial documentation or a standardR-059
Google preferred sources and personal context
Re-check due 2027-03 - Aofficial documentation or a standardR-099
llms txt
Re-check due 2027-03 - Aofficial documentation or a standardR-057
Perplexity sources and freshness
Re-check due 2027-06 - Aofficial documentation or a standardR-091
Search crawlers and training bots have different purposes
Re-check due 2027-03 - Aofficial documentation or a standardR-092
Why AI crawler blocking depends on firewall configuration
Re-check due 2027-03 - Bpeer-reviewed or a large controlled studyR-048
A study of citations to AI-generated documentation
Re-check due 2027-09 - Bpeer-reviewed or a large controlled studyR-094
Citations quotes statistics
Re-check due 2027-09 - Bpeer-reviewed or a large controlled studyR-096
Query fan out
Re-check due 2027-03 - Creputable industry data or observationR-097
AI overview top10 overlap
Re-check due 2027-03 - Creputable industry data or observationR-053
Baseline evidence on searches without external clicks
Re-check due 2027-03 - Creputable industry data or observationR-101
Crawler requests and referral visits measure different activity
Re-check due 2027-03 - Creputable industry data or observationR-045
Evidence on AI Overviews and organic click-through rate
Re-check due 2027-03 - Creputable industry data or observationR-103
Evidence on corroborating brand mentions across sources
Re-check due 2027-03 - Creputable industry data or observationR-049
Evidence on earned-media sources in AI citations
Re-check due 2027-03 - Creputable industry data or observationR-046
Evidence on visits to pages cited in AI Overviews
Re-check due 2027-03 - Creputable industry data or observationR-044
Evidence on when AI Overviews appear in 2026
Re-check due 2027-03 - Creputable industry data or observationR-100
Freshness answer engines
Re-check due 2027-03 - Creputable industry data or observationR-047
How faithfully AI Overviews represent source claims
Re-check due 2027-03 - Creputable industry data or observationR-051
Information agents and agentic booking
Re-check due 2027-03 - Creputable industry data or observationR-052
Reported consumer trust in AI search in 2026
Re-check due 2027-03 - Creputable industry data or observationR-050
Reported Google AI Mode adoption in 2026
Re-check due 2027-03
Other topics
- Access and crawlers18
- Agent readiness27
- Commercial12
- Content11
- Entities8
- Languages and regions7
- Measurement10
- Performance13
- Policies13
- Retrieval9
- Technical29
- Trust and provenance5
Every entry is searchable together in the full knowledge base. Vercatus plays cite entries by id. How the base is curated.