An official support document updated last evening has confirmed that Apple is using a web crawler service called Applebot to index the web for content used by its Siri personal digital assistant on iOS devices and built-in Spotlight search on both iOS and OS X.
An Apple-operated engine, Applebot is described as “the web crawler for Apple” which gathers useful content for products including Siri and Spotlight Suggestions. The document doesn't state how long AppleBot has been operational in production.