AI Search Engine Deep Dive
How Microsoft Copilot Works
The only AI engine that retrieves from both the public web and your organization's private data
Launched
February 2023
Monthly users
212M
AI model
GPT-4o / GPT-5
Web retrieval
Bing Search index
Org data
Microsoft Graph
Ads
Yes — sponsored placements
Microsoft Copilot is structurally different from every other AI engine in this series in one fundamental way: it has two completely separate retrieval layers. Every other engine retrieves from the public web. Copilot retrieves from the public web and from your organization's private data — emails, Teams messages, SharePoint files, meetings — simultaneously, in the same response.
For a CMO asking "what did we say to that prospect last week?", no other engine in this series can answer that question. Copilot can.
Everything on this page is sourced from official Microsoft documentation, official Microsoft Learn publications, and the official Microsoft Copilot blog. Where we don't have a verified source, we say so explicitly.
What is Microsoft Copilot?
Not one product — a system with four distinct tiers.
Unlike Perplexity or Claude which are single products, "Copilot" refers to a family of interconnected products at different price points and capability levels.
Tier 1 — Copilot (free): available in Windows, Edge, Bing. Web-grounded responses via Bing. Powered by GPT-4o / GPT-5. No organizational data access.
Tier 2 — Copilot Pro ($20/month): priority model access during peak times, Image Creator from Designer, Copilot Think Deeper (o1 reasoning).
Tier 3 — Microsoft 365 Copilot: full organizational data access via Microsoft Graph. Grounded in emails, Teams, SharePoint, meetings. Available inside Word, Excel, PowerPoint, Teams, Outlook. Enterprise data protection.
Tier 4 — Copilot Studio: custom AI agents built on Copilot. Connect to any data source. Low-code / pro-code development.
For AI visibility purposes, the most relevant tier is Tier 1 — the free Copilot that 212 million monthly users interact with via Windows, Edge, and Bing.
Technical architecture
How Microsoft Copilot retrieves and generates answers
Copilot has two completely separate retrieval layers that can operate simultaneously. Layer 1 retrieves from Bing's Search index for web content. Layer 2 retrieves from Microsoft Graph for organizational data (Microsoft 365 Copilot tier only). Understanding both layers is essential for a complete visibility strategy.
"Copilot's responses will now include more prominent, clickable citations and the option to see aggregated sources. Now, when Copilot provides an answer, it doesn't just deliver a summary — it shows you exactly where the information comes from, with relevant, clear, and clickable sources."
Microsoft Copilot Blog — "Bringing the best of AI search to Copilot", November 7, 2025
Prompt Received and Model Routing
User asks a question in any Copilot surface — Windows, Edge, Teams, Word, Outlook. Copilot's real-time router selects the appropriate model based on query complexity.
From official Microsoft Learn documentation: "By default, Copilot uses a real-time router to adjust the underlying model it uses based on your prompt. Quick response: For common or routine questions, Copilot prioritizes speed, using a high-throughput model to craft quick, succinct responses."
Layer 1 — Web Retrieval via Bing
Copilot retrieves from Bing's Search index — the same index that powers Bing Search. Critically: "Copilot uses Bing to search for results, but it does not crawl the websites that come up in the results. This means that only websites that were indexed by Bing are shown, and the fetched data is based on Bing's index, and not the current content of the website."
What this means for your brand: Bing indexation is the prerequisite for appearing in Copilot web responses. The crawler to allow is Bingbot. If Bingbot can't index your content, Copilot cannot retrieve it.
Layer 2 — Organizational Retrieval via Microsoft Graph
For Microsoft 365 Copilot users, a second retrieval layer activates: Microsoft Graph. This layer searches the user's organizational data — emails and calendar (Outlook), messages and meeting transcripts (Teams), documents and files (SharePoint, OneDrive), meeting notes and recordings, and any data accessible to the signed-in user.
The critical privacy point: Microsoft Graph retrieval only accesses data the signed-in user already has permission to see. Copilot cannot access data outside the user's permissions.
Copilot Search — Dedicated Search Mode
Beyond standard responses, Copilot offers a dedicated search mode. From the official Microsoft Copilot Blog: "We're introducing a dedicated experience directly within Copilot. Just click the drop-down and select 'Search' to get intelligently curated answers and even richer references and citations. Responses are adaptive, delivering concise answers for simple queries or in-depth summaries for analytical, or more complex queries."
Grounded Response with Clickable Citations
Copilot synthesizes retrieved data from both layers — web and organizational — into a response with clickable source citations. The response shows exactly where information comes from, with relevant, clear, and clickable sources.
For web-grounded responses, citations link to the Bing-indexed source pages. For organizational responses, citations reference internal documents, emails, or meetings.
What we know — and what we don't
Intellectual honesty is the point of this page. Most content about Microsoft Copilot optimization mixes verified facts with educated guesses without distinguishing between them. We don't do that.
Confirmed by official sources
- Copilot retrieves from Bing Search index for web content
- Microsoft 365 Copilot additionally retrieves from Microsoft Graph (emails, Teams, SharePoint)
- Bingbot is the crawler — standard Bing indexation is the prerequisite
- Real-time model router selects model based on query complexity
- Powered by OpenAI models (GPT-4o / GPT-5) under Microsoft's commercial agreement
- 212 million monthly users as of November 2025
- Copilot Search is a dedicated search mode within Copilot
- Paid placements available via Microsoft Advertising
- Microsoft Graph retrieval respects user permission boundaries
Not publicly disclosed
- The exact signals Copilot uses to select web sources from Bing results
- Whether domain authority is separately weighted beyond Bing's standard ranking
- The precise freshness signals used in Copilot's web retrieval
- How organizational data and web data are balanced when both are available
Ads in Copilot: Paid Placements in AI Responses
Copilot is one of two engines in this series where paid placements are explicitly available (the other being Google AI Overviews).
Sponsored placements appear in Copilot responses labeled "Microsoft Advertising" and "Sponsored." These are Performance Max campaigns that automatically qualify for Copilot conversational placements.
From Microsoft's Jordi Ribas, Corporate VP of Search & AI: "We're focused on hybrid architecture. Structured cards for certain categories like weather, travel, shopping. Generative text for deeper research."
This creates a two-track visibility strategy for Copilot: organic (Bing indexation + strong SEO) and paid (Microsoft Advertising Performance Max campaigns). For brands with advertising budgets, Copilot is the only non-Google AI surface where you can pay to appear alongside organic citations.
Gemini vs ChatGPT Search vs Perplexity vs Microsoft Copilot
The same question, three completely different systems.
| Gemini | ChatGPT Search | Perplexity | Microsoft Copilot | |
|---|---|---|---|---|
| Web retrieval | Google Search (grounding) | Bing + partners | Proprietary RAG | Bing index |
| Org data access | No | No | No | Yes — Microsoft Graph |
| Underlying model | Gemini 2.5 | GPT-5 | Proprietary | GPT-4o / GPT-5 |
| Crawler to allow | Google-Extended | OAI-SearchBot | PerplexityBot | Bingbot |
| Paid placements | No | Yes (free tier) | No | Yes — MS Advertising |
| Enterprise integration | Google Workspace | Limited | None | Deep — M365 ecosystem |
| Monthly users | 650M app + 1.5B via AIO | 800M weekly | 22M active | 212 million |
The critical insight: Copilot is the only engine where your brand's presence in internal organizational data directly influences how an AI describes you — to the employees and buyers who are already your customers. When a procurement manager at a Fortune 500 company asks Copilot about your product using Teams or Outlook, Copilot draws from your previous emails, proposals, and conversations with that organization. No external optimization can replicate what you've already established inside their Microsoft ecosystem.
Practical implications
What this means for your brand's visibility
Five implications derived directly from Microsoft Copilot's confirmed architecture.
1. Bing indexation is the web prerequisite
Copilot retrieves from Bing's index. If Bingbot cannot crawl and index your content, your brand cannot appear in Copilot's web-grounded responses. This is separate from Google indexation — both matter now.
Source: Microsoft official + Zenity Labs technical breakdown
2. Your existing relationship with a customer influences Copilot responses
For Microsoft 365 Copilot users, the AI draws from their organization's emails, meetings, and files. If your brand has had strong, positive interactions documented in a prospect's Microsoft ecosystem, that context directly feeds how Copilot describes you to that user.
Source: Microsoft Learn — Microsoft Graph retrieval
3. Bing SEO is not optional — it's a separate track
Most brands optimize for Google and ignore Bing. With 212 million Copilot users retrieving via Bing's index, Bing indexation has become a first-class AI visibility requirement.
Source: Microsoft Copilot Blog + Microsoft official
4. Performance Max campaigns now reach Copilot
If you run Microsoft Advertising, your Performance Max campaigns automatically qualify for Copilot sponsored placements. This is the only engine in this series (besides Google AI Overviews) where paid visibility is explicitly available alongside organic.
Source: Microsoft Advertising official documentation
5. The enterprise flywheel: better proposals lead to better Copilot visibility
For B2B brands, every well-documented interaction with a Microsoft 365 customer — proposal, email thread, Teams meeting — becomes context for Copilot's future responses to that customer. The quality of your written enterprise communications directly feeds your AI visibility within that account.
Source: Microsoft Graph architecture, Microsoft Learn
Frequently asked questions about Microsoft Copilot
How does Microsoft Copilot retrieve information?
What crawler do I need to allow for Copilot?
Are there ads in Copilot responses?
How does organizational data affect Copilot responses?
How is Copilot different from ChatGPT if both use OpenAI models?
Sources cited on this page
Every factual claim on this page is sourced. We link to primary sources directly.
- Microsoft Learn — Overview of Microsoft 365 Copilot Chat [source] Official documentation
- Microsoft Copilot Blog — Bringing the best of AI search to Copilot — November 2025 [source] Official documentation
- Microsoft Learn — Copilot Studio release notes [source] Official documentation
- Wikipedia — Microsoft Copilot (history, versions, user stats) [source] Reference
- Zenity Labs — Inside Microsoft 365 Copilot: A Technical Breakdown [source] Reference
- Aggarwal et al. — GEO: Generative Engine Optimization, KDD 2024, Princeton / IIT Delhi — 2024 [source] Academic paper
Other AI search engines
The world's most used AI — and why it plays by completely different rules than Perplexity
Read deep dive → ClaudeThe reasoning engine that searches when it needs to — not by default
Read deep dive → Google GeminiOne model, many surfaces — and one robots.txt tag that determines if your brand gets cited
Read deep dive → Google AI OverviewsThe AI feature that reaches more people than any other product in the world
Read deep dive → GrokThe only AI engine trained on real-time social media data — and what that means for your brand
Read deep dive → Perplexity AIThe answer engine that cites its sources
Read deep dive →Does your brand appear when your prospects ask Microsoft Copilot about what you do?
Most brands don't know. Storyzee runs systematic prompt testing across Perplexity, ChatGPT, Gemini and Claude — and turns the results into a score out of 100 with a prioritized action plan.