Here is a reference post from Appleinsider that is worth looking at on the new and improved Spotlight that comes with OS X 10.10, Yosemite. I've been using it since it came out last week and I'm loving how fast and powerful it is.
In fact, it kinda made me wonder how inefficient I was before.
Calculator, currency conversions, movie times, and search results as well as easy to understand privacy settings for us paranoid folks. All done the Apple way which means everything is presented beautifully and easy to use.
I would love to see this translate over the iOS, particularly on the iPad.
What would really make take Spotlight up another level is for Apple to merge Siri with Spotlight on the Mac soon. What are missing are results likesports scores, weather, and other inquires that we don't quite need to go to the search engines to find.
And yes, while some of the search results do come from search engines, Apple is slowly peeling away the layers of search one result at a time to deprive Google in particular of valuable search revenues. If users can find what they need in Spotlight without having to go to the Web, that means there will be less tracking for Google and ad revenues.
What's that Chinese saying? Death by a thousand cuts? Well, Apple won't quite kill off traditional search this way. But it is making search engines less and less relevant for a sizable amount of inquiries.