Bing Smart Search was first introduced as part of Windows 8.1 this last fall allowing you to swipe or type from your Start screen to find what you need like documents on your PC, a photo album in the cloud, your favorite app, or a website. Today, Bing has announced they are making improvements to Smart Search in Windows 8.1
Improvements include making search more natural. For example, if you are unclear on where to go to find new apps for Windows, you can search “get apps for windows” where Smart Search will showcase the Windows Store. Bing has taken some of the most common tasks people perform in Windows 8.1 to have Smart Search show results based on natural language understanding.
Bing has also done some work to improve common spelling mistakes in the Smart Search bar and to showcase more apps that might be relevant to your search.
For more, see their blog post here