Microsoft’s new digital assistant, Cortana, is still in beta. After a brief hands-on, however, it already appears to be just as capable as Google Now and somewhat ahead of Apple’s Siri.
Digital assistants are somewhat like real assistants: They can provide you a list of their skills, but only after working with them for some time can you better assess their talents. And so it is with Cortana: Without actually giving Microsoft your data, you can’t quite know for sure how it will shape up.

A list of” interests” that Cortana monitors.
Nevertheless, Cortana is one of Microsoft’s most eagerly awaited improvements. She—three executives, speaking separately, consistently referred to Cortana as a “she”—will be part of Windows Phone 8.1, debuting in new Lumia Windows Phones from Nokia this summer. Microsoft announced Windows Phone 8.1, as well as Windows 8.1 Update and a long list of other new or refreshed products, on Wednesday at its Build conference in San Francisco.

The Cortana “Notebook”.
A few years ago, digital assistants were applications that could manage your email inbox. Cortana can—if you allow her to—read your inbox, log into your Facebook account, post tweets, and play music. Like Google Now, Cortana can sniff out plane departure times or locate the closest Chinese restaurant. And, with Microsoft’s latest generation of Bing technology powering Cortana, it can listen and respond to natural language, allowing you to speak to it conversationally, rather than trying to use predetermined commands.

“Find Chinese restaurants near me.”
But she’s not perfect. Inside the Moscone West convention center in San Francisco, Cortana was convinced that I was in Atlanta, Georgia (and no, executives said it was not running over a VPN). While I could text “people” listed as contacts and stored in a demonstration phone, I couldn’t email them. (I didn’t confirm whether they were programmed with email addresses, however.)
With Cortana, you have the option of giving her (gah!) all your information, some, or none at all. Cortana actually works a lot like a targeted ad: The more information you provide, the better she performs. At least with her, you have some choices: You can tell Cortana what you’d like her to monitor in categories like “Out and About,” “News,” “Daily Routine,” “Sports,” Travel,” “Weather,” and more. Cortana can also keep track of your music searches (to build a profile of what you like or dislike), offer to set reminders, and establish an “inner circle” of friends who can contact you even during time you’ve designated as “quiet hours.” All of this is stored in the Notebook, a giant Settings menu that’s open to the user.

Another win for Cortana.
That doesn’t mean you have total control, however. Chris Weber, the executive vice president of sales and marketing for Nokia, showed me his Windows Phone 8.1 device. Cortana independently chose to monitor news about Microsoft, as well as the Seattle Seahawks, his hometown team.
In general, Cortana did pretty well with my queries. Requests like “What’s the best Chinese restaurant near here?” produced a list of top-rated restaurants on Yelp, organized by proximity and shown on an accompanying map. (A similar request for restaurants serving jambalaya didn’t work, however.) A follow-up request displayed the traffic.
Cortana addressed factual requests well, including the heights of the Eiffel Tower and Mt. Everest. Asking “who is the secretary general of the United Nations?” returned a Bing query, with Ban Ki-moon correctly called out. But asking how long it took to fly from San Francisco to Seattle (a query Google Now failed to answer, but Wolfram Alpha did) generated an unproductive Bing search. Asking it to “play YouTube cat videos” also brought up a Bing page, although with the correct results.

A list of suggested queries.
Both Google Now and Cortana “geofence” requests. If you ask either digital assistant to remind you to buy eggs at the supermarket, it will search for a list of available supermarkets near you. Google Now knows the market I shop at, although granted, I’ve used it for a much longer period.
But in the keynote presentation, one Cortana feature stood out: Microsoft’s Joe Belfiore told Cortana to remind him to ask his sister about her cat. Knowing who you’re talking to is a feature Google Now doesn’t have, yet.
What Cortana does is put Microsoft and Google neck-and-neck in the race to know more about you, and provide you with useful information. Will they go too far, and cross the so-called “creepy line” in a bid to one-up the other? It’s a valid concern, and one that bears watching.