We discussed the evolution of voice-based personal assistants in the previous section. In this section, we shall extend that discussion to some of the popular uses of each of the interactive voice-based personal assistants, irrespective of whether the assistant in question is desktop, smartphone, or smart home-based. We shall begin with one of the earliest and most well-known ones, Apple's Siri.

As indicated earlier, Siri started as a separate smartphone app in 2011 for iOS, which was later on acquired by Apple. Initially, the capabilities of Siri were limited to smartphones and simple functions such as:

• Looking up contacts
• Messaging (SMS)
• Fetching weather updates on user demand, plus other simple queries as mentioned in the previous section

However, Apple's roadmap also extended the capabilities of Siri by closely integrating it with third-party apps and, true to their promise, with the coming of iOS 10, Apple also released SiriKit.

If the user has the following third-party apps installed, he/she can request a ride using Siri:

• Uber
• Lyft

If the user has the following third-party apps installed, he/she can set those to send a message (and not just an SMS) using Siri:

• WhatsApp
• LinkedIn
• WeChat
• Slack

A user can also make VoIP calls using the following apps via Siri:

• Skype
• Viber

Siri can also help a user to:

• Search files on his/her Mac
• Notify the user about their storage space
• Send requests to FaceTime with Contacts, and many others as shown here:

With a fair idea about Siri's desktop and smartphone capabilities, let's now move on to another popular voice assistant.

We are going to discuss the Android and Google Now next, which at the time of writing is the biggest player in the smartphone market and also the home of Google Now, the voice assistant introduced by Google for Android smartphones in 2012.

In early 2010, the smartphone market was dominated by many players. Over the years, this has filtered down and only two major players remain in the market as depicted as follows:

Google Now can do pretty much all that Siri can accomplish; however, it has better integration with the web and web-based queries, since the web is Google's main forte. Some of the things that a user can ask Google Now are:

Apart from Google Now, Google also has introduced Google Assistant, which is a more evolved version of Google Now, given the fact that the user can hold full-length conversations with Google Assistant, which is not possible with Google Now.

It is very likely that Google Now will be phased out and Google Assistant will take its place; however, Google Assistant is currently only available on Google Home, which is Google's smart home speaker; the Android Pixel 2 smartphone; and for Android Wear:

Now, moving on from the smartphone market to the desktop market:

As shown in the preceding graph, as of January 2017, the desktop market had Windows, Linux, and Mac OS X as major players, with Microsoft being the dominant force, which brings us to our next personal assistant.

With Microsoft's clear dominance of the desktop market, we cannot ignore Cortana, which is Microsoft's answer to Siri and Google Assistant, but focused on desktop and Windows Mobile:

Not just limited to Windows 10, Windows 10 Mobile, and Windows Phone 8.1, Cortana is also available for:

• iOS (as a separate app)
• Android (as a separate app)
• Xbox One
• Invoke smart Bluetooth speaker by Harman Kardon

Some of the many things that Cortana can accomplish are:

• Web-based queries using Bing Search (for example, "Who is the President of the United States?")
• Launch apps and turn on/off Wi-Fi/Bluetooth
• Ask about weather
• Manage appointments, reminders, and events

With that, we come to discuss the Star of this book.

Alexa, the whole center point of this chapter and the book, is the interactive voice-based personal assistant by Amazon, originally introduced with its family of Echo devices. Alexa as an assistant is oriented towards a smart home concept, hence most of its use comes from Amazon Echo, a smart speaker designed and developed to be kept in the living room of the user's home so that the user can ask it day-to-day queries about weather, food recipes, and jokes, or play interactive trivia games, set alarms, shop for day-to-day items, and much more. The following diagram shows some of the things that a user can ask Alexa:

The capabilities of Alexa can also be extended by installing third-party skills (similar to Google Home's third-party apps). Each third-party skill is meant to serve a specific purpose. For example, the Uber skill allows you to order a ride, the Domino's skill allows you to order a pizza—all from the comfort of your home and through the magic of your voice working together with Alexa.

As of the time of writing this, there are more than 15,000 skills available for Alexa with Uber and Lyft being the most used ones in the travel category, Pandora and Spotify for music streaming, and multiple other skills being utilized in home automation.