Cortana's also powered by Bing, but uses machine learning to provide a personalized summary of your day, surfacing calendar details and news she thinks you'll find interesting when you open the interface. Cortana responds to voice commands as easily as typed ones, and also understands natural language commands. You can tell Cortana to "Find pictures from June," for example, and the assistant will even include your OneDrive-stored files in the results. Simply put, Cortana's great--as long as you don't mind providing personal info to Microsoft.
Plus, Cortana's sassy--though not all of the cool easter egg questions that Cortana answers on Windows Phone work on the Windows 10 desktop just yet. (Be sure to ask Cortana what she thinks of Siri!)
10. Windows Hello
Windows 8 had the usual authentication options--PIN code, password, yadda yadda yadda. Nothing lacking, but nothing exciting either, in other words.
Windows 10 kicks things up a notch with enhanced support for two-factor and biometric authentication, spearheaded by the awesome Windows Hello feature, which (among other things) can use depth-sensing cameras to automatically log you in.
As PCWorld's Mark Hachman wrote in his Windows 10 pre-review after spending some hands-on time with Hello:
"Boy, Hello is terrific. You simply train' the machine by letting the PC camera look at you for a moment or two. Thereafter, when you sit down at your PC, it recognizes you and logs you in--no effort required. And if you share that PC with others in your family, it will recognize them, too, automatically logging them in and picking up where they left off."
Facial recognition is nothing new, but Hello's flavor of it sounds uniquely special. Too bad it'll only work with a handful of PCs when Windows 10 launches.
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