A new holiday-themed TV spot from Apple reveals how Siri, the company's virtual personal assistant found on the new iPhone 4S, can be used for even the most monumental of tasks. In the advertisement, we see old St. Nick himself Santa Claus traveling around the world on Christmas Eve, employing Siri to easily get directions to children's houses, retrieve local weather from global regions instantly, and check his old e-mail for his Naughty and Nice list.

Siri can help anyone get through a busy day... Or night, reads Apple's description of the video.

Siri even reads aloud a new text from Mrs. Claus, advising the old elf to go easy on the cookies. But best of all, as Santa rides across the sky in his sleigh, he asks Siri for a reminder of how the rest of his day looks. Siri's reply: You have 3.7 billion appointments.

With Siri, Apple has proved that it can make virtual assistants both useful and friendly. The technology, which helps users call, text, e-mail, schedule meetings, surf the Web and find answers to complicated context-sensitive questions, was born out of a $150 million project from DARPA and SRI Ventures, the largest artificial intelligence project in U.S. history to date. The unique feature has driven sales of the iPhone 4S to make the new smartphone one of the most successful product launches in the company's history.

Siri is one of the key reasons people love Apple's new iPhone 4S. In a survey of 215 iPhone 4S owners between Nov. 2 and Nov. 9, 96 percent of respondents said they were very satisfied or satisfied with the iPhone 4S. Only two percent said they were unsatisfied. Of all of the various reasons, 49 percent of owners named Siri the best feature on the handset. 

Besides Siri, 39 percent of respondents praised the ease of use on the new iPhone as its best feature, and 33 percent dug the updated camera system, which features an 8-megapixel camera that can shoot video in full 1080p HD.

Siri is currently in beta on the iPhone 4S. Many believe that it will become a fully realized service in the upcoming iPhone 5 and iPad 3, both believed to debut in mid-to-late spring 2012.