Apple is hard at work for making it's entry to the Search industry. It's crawler, AppleBot is now scouring the web for results and you may have seen this in your server logs:
Mozilla/5.0 (Macintosh; Intel Mac OS X 10_10_1) AppleWebKit/600.2.5 (KHTML, like Gecko) Version/8.0.2 Safari/600.2.5 (Applebot/0.1; +http://www.apple.com/go/applebot)
Given Apple's Significant market share in mobile devices and embedded search in iOS and OS X operating systems - this could be something that will be able to make a significant dent in Google marketshare. It is likely that the approach and results are Similar to that of Bing - significant in the US and UK, but not that relevant outside the english speaking work.
Given the nature of SEO business and the lack of a public release from Apple there are no certain terms at this point. From the acquisitions Apple has made, the Topsy deal is the most interesting and gives us an idea of how to perform Search Engine Optimisation for Applebot.
If you send a Tweet on Twitter, you will get an immediate response - So Apple's search is clearly tapped to the Twitter firehose.