Ask a traditional search engine “what’s the best way to store fresh basil?” and you get ten links to read. Ask an answer engine and you get a paragraph that says what to do, with small citation markers pointing to the pages it drew on. Perplexity, Google’s AI Overviews and AI Mode, ChatGPT search and Microsoft Copilot search all work this way.
Under the hood an answer engine is retrieval-augmented generation over the web. It turns the question into one or more searches, fetches and reads the top results, and has a large language model write an answer grounded in those pages, citing them. OpenAI’s WebGPT research system showed the pattern in 2021 by letting a model browse and quote pages before answering.
The design changes who does the checking. A list of links leaves judgment to the reader. A confident paragraph invites the reader to accept it. Liu, Zhang and Liang audited four generative search engines and found answers that read well but were often unsupported: on average only about half of generated sentences were fully backed by their citations. In episode 54 at 1:05:26, Dan Klein frames the general problem: “If you have a technology that always sounds right, but often isn’t, it becomes very hard as a user to know what to trust.” That is his view of language technology broadly, not a measurement of any one product. The episode was sponsored by Galileo (sponsor mention).
Why it matters (editorial synthesis): answer engines are becoming the first stop for many questions, which is convenient and also shifts traffic away from the sites the answers come from. For readers, the practical habit is to open the cited source for anything that matters and check that it actually says what the answer claims, especially for health, money and legal questions. For publishers, it is the reason generative engine optimization has become a topic.
Hear it from the guest
“If you have a technology that always sounds right, but often isn't, it becomes very hard as a user to know what to trust.”
Quotes lightly edited to remove filler words.
Sources
- Perplexity Help Center: How does Perplexity work? — Product documentation explaining that Perplexity interprets a question, searches the web in real time and returns a conversational answer with cited sources; checked October 24, 2026.
- Google Search Central: AI features and your website — Google's guidance on AI Overviews and AI Mode, which show AI-generated answers with links to supporting web pages; checked October 24, 2026.
- Liu, Zhang and Liang: Evaluating Verifiability in Generative Search Engines — Audit of four generative search engines finding their answers fluent but often unsupported: on average only about half of generated sentences were fully supported by their citations; checked October 24, 2026.
- Nakano et al.: WebGPT: Browser-assisted question-answering with human feedback — OpenAI research system that searched and browsed the web, then wrote answers that cite the pages it used, an early version of the answer-engine design; checked October 24, 2026.