Microsoft's Cortana Gets Her Bing On For More Personal Searches
The video below gives a nice overview of how that works.
In order to make the Bing experience even more personal, Microsoft has rolled out personalized “cards” on the Bing homepage that will give users a similar experience on the desktop as well as on Windows-powered tablets and smartphones.
You set it up by logging in to your Microsoft account and clicking various items (such as news or weather) or the little stars next to search results indicate your interests. Then, Bing and Cortana will keep track of those items and notify you of changes across your Windows devices.