Next time you schedule a meeting and an assistant named Amy or Andrew Ingram sets up the logistics, here's a pro tip: You may be chatting with a robot. And if it's one of x.ai's bots, you might never know the difference. That was my experience when I exchanged emails with "Andrew" to set up an interview with x.ai's CEO. After I emailed x.ai's press contact, she referred me to Andrew to hammer out the details. Andrew proposed a time, thanked me when I accepted and sent out a calendar invitation.

For years, Apple's Siri digital assistant has skulked in the corner of iOS, usually assisting only when asked. Like the wallflower who gets a summer makeover, however, the new Siri that steps out with iOS 9 this fall will be outgoing and eager, bounding forward to help. Siri's upgrade (revealed at Apple's Worldwide Developers Conference on Monday) emphasizes proactivity and has achieved parity with the primary features of Google Now and Microsoft's Cortana: time- and location-based reminders, hunting down videos that can be played within an app, identifying contacts via their phone number, or launching particular songs. But several of Siri's promised features actually push the platform ahead of the competition: pulling useful data from your apps, controlling your smart home, and kicking off specialized tasks based on your habits or current needs. Now that the power balance is shifting, here's how Siri stacks up to her competition.

Via rumors and other leaks, we've known for a while now that Microsoft's digital assistant, Cortana, should appear in Windows 10. Now, a video appears to prove it. WinBeta obtained the code to either Cortana or a leaked build with the Cortana executables built in, and gave Cortana a spin. Because the assistant isn't actually connected to the cloud services, Cortana throws up an error message when it's time for her to do anything truly useful. It's also early days as far as the UI is concerned: Cortana looks a little rough in this version, but she'll be spiffed up by the final release, we'd bet.

In 1966, some Massachusetts Institute of Technology researchers reckoned that they could develop computer vision as a summer project, perhaps even get a few smart undergrads to complete the task. The world has been working on the problem ever since. Computer vision is where computers recognize objects like people do. It's one of a number of tasks we consider essential for generalized artificial intelligence, in which machines can act and reason as humans do. While we've been making some considerable headway in computer vision, especially in recent years, that it has taken 50 years longer than expected shows why AI (artificial intelligence) is such as difficult and elusive goal.

Fresh off a nearly perfect run predicting the outcome of World Cup futbol matches, Microsoft's digital assistant, Cortana, has focused her abilities on picking the winners of NFL football games. Need help predicting whether or not the Seahawks will hold off the Green Bay Packers? The kicker, of course, is that you'll need access to Cortana, Microsoft's digital assistant. And for right now, that means a Windows Phone 8.1 phone, either one that's been upgraded via Microsoft's developer program or as part of the "Cyan" rollouts that Microsoft and its carriers are pushing to vanilla Windows Phone 8 Lumia phones. For one, asking Cortana about the outcome of a particular game is a bit like a magic spell: You'll need to ask Cortana "Who will win Team A or Team B?" and she will provide an answer.

If you ask Siri, the virtual personal assistant on the iPhone 4S, why it's so great, it answers with disarming humility: "I am what I am." But industry insiders say there's a little more to it than that. Siri goes well beyond voice recognition, they say, by applying powerful artificial intelligence and statistical analysis to decipher the meaning behind questioners' sometimes jumbled sentences. Add to that Siri's dry wit and you have the kind of breakout hit that will propel new uses of similar technology on your phone, tablet, and even your PC, experts say. Services like Siri are "natural language processing" apps that use statistical models to figure out what you probably meant to say when your pronunciation or word choice is garbled.

Microsoft said Wednesday that it has added natural-language search to its internal Windows 8 Smart Search. Users can write out queries as sentences or thoughts, rather than try to puzzle out the correct search term. Users must be "updated to the latest release of Windows 8," the Bing Relevance Team said in a blog post. Users apparently don't need to download an update; the improvements will just appear. "One of the most exciting things about this feature is that it demonstrates how the Bing platform makes our Windows product more useful and helpful without having to update the Windows client software," the Bing team wrote.

In the battle for hearts, minds, and intelligent helpfulness, Microsoft plans to wage war against Siri and Google Now with the help of the most full-featured digital assistant ever imagined. No, not Microsoft Bob--stop your snickering--but Cortana, the faithful, blue-tinged AI that helped the Master Chief win the war against the Covenant hordes in the legendary Halo series of video games. Early leaks of the impending Windows Phone 8.1 update have featured an app dubbed "zCortana," and according to ZDNet, WPCentral, and The Verge, Cortana is the codename for a voice-controlled, adaptable digital assistant--kind of like Siri, but smarter. A Windows Phone 8.1 build acquired by The Verge shows that Microsoft is already testing Cortana's ability to pull in notifications, weather and location info, calendar details, and more, and "she" also has access to the phone's Bluetooth capabilities. Bing's Satori engine--a massive knowledge database, named after the first step on the Buddhist path to enlightenment--is said to be the brains behind Cortana.

Robin Li, head of China's web giant Baidu, unveils the firm's intelligent digital assistant, Duer. When Andrew Ng joined Google from Stanford University in 2011, he was among a trickle of artificial-intelligence (AI) experts in academia taking up roles in industry. Five years later, demand for expertise in AI is booming -- and a torrent of researchers is following Ng's lead. The laboratories of tech titans Google, Microsoft, Facebook, IBM and Baidu (China's web-services giant) are stuffed with ex-university scientists, drawn to private firms' superior computing resources and salaries. "Some people in academia blame me for starting part of this," says Ng, who in 2014 moved again to become chief scientist at Baidu, working at the company's research lab in California's Silicon Valley.

In a previous column I mentioned the Amazon Echo ($179 on Amazon.com) as a useful device for listening to music and podcasts. But, after using the Echo for the past month and hearing others talk about it at CES, I've come to the conclusion that it's far more than that. I bought the Echo as a music player because I was impressed at how easy it is to use your voice to play songs from your own music library that you've uploaded to Amazon Music along with the million or so songs on Amazon Prime Music, your Pandora playlists and the podcasts, music and online radio stations on TuneIn and iHeartRadio. You address the Echo as "Alexa," Amazon's persona that's equivalent to Siri or the OK Google voice commands for Android devices. Amazon also gives you the option to address Echo as "Amazon," but I prefer calling her Alexa.