Google Caffeine
Google Caffeine was the new web index Google finished in 2010, built to add pages faster so search results could be fresher.
Google Caffeine was a new system for building Google's index, the store of pages Google searches when you type a query. Google announced it was finished in June 2010. Its point was speed: new pages, blog posts and news stories could appear in results much sooner after they were published.
Caffeine was about how Google stored pages. For marketers, it meant new content could be found and shown far faster than before.
Why the index matters
When you search Google, you aren't searching the live web. You're searching Google's copy of it. Google's own analogy is the index at the back of a book. If a page isn't in the index yet, it can't show up, however good the page.
Google's old index was built in layers, and the main layer was updated every couple of weeks. Caffeine updated the index in small pieces, all the time.
The same question in AI search
Freshness is still a question in AI search, and it works on two clocks. A platform that searches the web before answering can find a page soon after a search engine indexes it. What a model learned in training only changes when the model is retrained, which can be many months later.
For example, if Fernhill Coffee launches a new decaf blend on Monday, an answer that searches the web might mention it within days, once the page is indexed. An answer from the model's memory alone won't know about it until a later version.