Apple's personal digital assistant Siri can help you find gifts at Best Buy thanks to a recent feature added to Wolfram Alpha. The so-called computational knowledge engine has tapped into Best Buy's public data of over 35,000 products to help you find and compare products. For example, you could use Wolfram Alpha to compare specs and user ratings for tablets such as theBlackberry Playbook and the Asus Transformer Prime just by asking Siri.