The iPhone's virtual digital assistant, Siri, has gotten the world used to engaging in conversations with computers. With Windows 10, Microsoft is bringing its personal digital assistant, Cortana, to the desktop (as Apple is expected to later with Mac OS X). Google Now has brought a similar capability to Android phones, but that feature lacks the personality of a Siri or a Cortana. In fact, Cortana was specifically designed to have a personality, and will answer sassy questions with witty retorts and even tell you a joke if you ask her to.

But she (yes, we refer to Cortana as she, as Microsoft does) was also designed to incorporate the conditional intelligence of Google Now, and even to take it a step farther. For example, you can ask Cortana to remind you to call your wife when you arrive at Costco. This geo-fencing requires Cortana to know what your wife's name is in your contacts list and where you are at the moment.

It's important to know that in the current Technical Preview build, Cortana is severely limited compared with even the released Windows Phone version of the assistant and compared with what will be in the released Windows 10. For example, on the phone, she can launch apps, but that feature isn't yet implemented on Windows 10 for the desktop. For other situations where you'd expect a direct answer or an action, you'll just get web results in a browser window.

Cortana differs from both of the other two digital assistants in that she gives you control over what she knows about you. Cortana also becomes the default search on Windows Phones and Windows 10 desktops—you can simply hit F5 to summon her for this. Google Now, by comparison, simply watches what you search for and incorporates that into your interests it displays info about.

As with Cortana on the phone, on Windows 10 desktops, you don't have to use your voice: You can also simply type your question into her text box. And unlike Siri and Google Now, Cortana is more than just a question answering or reminder creation tool: Cortana pops up your Daily Glance, a digest that includes things like sports results for teams you follow, news stories based on your interests, and local weather.

Hey, Cortana and Other Settings
As with Google Now and now Siri, you can set up Cortana to respond hands-free to your voice. You do this by saying "Hey, Cortana." To enable this, tap Cortana's circle in the left side of the taskbar, then open the three-line (aka "hamburger") menu, and choose the last choice, Settings. From here, you can turn off Cortana completely if she creeps you out. You can also tell her what to call you and whether to call you by name.

Other options include allowing Cortana to scan your email to inform you about travel updates and shipped packages.

The Notebook
How does Cortana know about you? One major way is through the Notebook. Cortana's Notebook is one aspect that differentiates her from Siri and Google Now. When Microsoft staff were developing Cortana, they interviewed actual human personal assistants, and found that most of them kept notebooks of key data on their employers. Cortana's Notebook is where you set up your interests, calendar, and daily routine. If you have a fitness tracker, you can include its reports in your Daily Glance, and you can specify whether you commute by car or transit. You can have Cortana remind you when it's time to go to or leave from work. And for sports teams, you can have her show scores or hide them.

Cortana's Trip Planner can tell you how long it will take you to get to the airport, along with the weather at your destination.

Reminders
Reminders in Cortana can be based not only on time, but also on place. That is, you can tell her to remind you to do something when you've arrived at a specified location. For example, "When you get home, call your uncle."

Places
How does Cortana know when you've arrived at home or work or your favorite restaurant? She knows because you've told her what those locations are when searching on Maps. When you tap on a spot in the default Maps app, you get choices to set that location as your home or work location.

Cortana can also remind you to do something based on types of locations as well as specific locations. For example, you can say "Hey Cortana, Remind me to buy eggs when I'm at any supermarket." And keep in mind that by setting up the reminder on your Windows 10 PC, it will appear for you later on your Windows 10 phone if you're signed into the same Microsoft account on both.

Jokes
For those times when life is taking its toll on you, Cortana will always be there with a joke to cheer you up. Okay, her sense of humor hasn't quite caught up with Louis C.K. or even Jack Benny. A couple samples we got were "A Roman walks into a bar, holds up two fingers, and says "Five beers, please." and "What did the passive-aggressive Raven say? "Nevermind. Nevermind." Watch the video below for more.

More Cortana to Come
As with everything in Windows 10 Technical Preview for desktop PCs, Cortana is very much a work in progress. Cortana won't even open apps yet, as she's been able to do for over a year in her Windows Phone incarnation. She'll also be able to find and play music from any Windows devices on the home network, and to show, for example, photos from your trip to Hawaii on demand.

For more on Microsoft's upcoming operating system for desktops, laptops, tablets, and smartphones, head to PCMag's Windows 10 hub page. You can also read our Hands On with Windows 10 for Phones, and with Windows 10 for PCs.