What search engine does Siri use?

Siri is powered by and uses the Bing search engine, which is a product of Microsoft.

Why would Siri use bing?

Two reasons come to mind:

1. Apple don't have their own proprietary search engine. This means Apple has to strike up a partnership with another company to provide this service.
   
   

   

2. Choosing Bing over search engine market leader Google is also a no-brainer. It would be inconceivable for Google to help Apple develop their mobile products, seeing as Google-owned Android is the iPhone's main rival.

What's also interesting is that Bing powers another voice-commanded mobile assistant application: Cortana, which features in all Windows Phones.

It'd be interesting to compare search results queried through Siri and Cortana to work out whether Bing is providing the same search algorithms to both products.